Day 2 :
Keynote Forum
Sergey Klimosky
Lomonosov Moscow State University, Russia
Keynote: The optical properties of dichroic doped NCS glasses
Biography:
Sergey Klimosky has completed his PhD from Lomonosov Moscow State University in 1990. He is the Associate Professor of Faculty of Materials Science. He has published more than 50 papers in reputed journals. In recent years he has worked in the field of physics and chemistry of photonic crystals and other optical materials.
Abstract:
The Lycurgus cup, a remarkable example of a late roman glass, is famous for its dichroism, that is, the ability to change color depending on the direction of light. It is cut from a piece of NCS glass, containing small amounts of iron, calcium, phosphorus, silver and gold. After striking the glass is semi-opaque, being red in transmitted light and green in reflected light. The optical properties of the glass are usually explained by light absorption and scattering by bimetallic AgAu nanoparticles. In this work, we show that AgAu nanoparticles play an important role only in the red color generation due to the absorption of green light. We have synthesized dichroic samples and have found that the green color in reflected light is due to the light scattering on droplets of silica-phosphate glass containing cristobalite crystallites in combination with the absorption of Fe3+. For the droplets formation process both iron oxide and calcium phosphate as doping agents are important. The role of iron, that is present in glass predominantly in the ferric form, is very important as it not only gives the green color to the glass, but also causes the phase separation. The change of iron to manganese doesn't provoke phase separation and the glass obtained remains transparent after striking and has reddish violet color in both transmitted and reflected light. The glass prepared without calcium phosphate also remains clear. Thus, the dichroic properties are due to both AgAu nanoparticles and to calcium phosphate and iron content.
Keynote Forum
Ali Masoudi
University of Southampton, UK
Keynote: Distributed acoustic sensors: Evolution and applications
Biography:
Ali Masoudi is a Postdoctoral Research Fellow in the Optoelectronics Research Centre (ORC) at University of Southampton with broad experience in distributed optical fibre sensing systems. He received his PhD in 2015 for his work on distributed optical fibre dynamic strain sensors. He is currently working on an EPSRC grant to develop a distributed fibre optic acoustic sensor for railway signalling and health monitoring as well as RAEng seed grant for smart city project. His research interest includes distributed optical fibre sensors (DOFS) including distributed acoustic sensors (DAS), distributed shape sensing, distributed optical fibre magnetic field sensing, and micro-fibre and nano-fibre current sensors. He has published >15 papers in international scientific journals/conferences, authored 2 patents and given 5 invited talks.
Abstract:
The volume of research on distributed optical fibre vibration sensor, also known as distributed acoustic sensor (DAS), has increased substantially in the recent years. DAS systems owe their rising popularity to their capability of mapping vibrations along tens of kilometres of fibre. Sensing fibres can be installed in inaccessible spaces and can be engineered to withstand harsh environmental conditions. The sensing principle of DAS allows the interrogation unit of such systems to be kept at a safe distance while the sensing fibre connected to the interrogation unit can be encapsulated in several protective layers to withstand harsh conditions. The rising demand for DAS systems stem from a number of sectors including structural health monitoring (SHM) in aviation industry and civil engineering, borehole monitoring in geophysical sciences and oil industries, and real-time monitoring of complete rail and road networks for rapid decision and response. In this presentation, the principle of distributed optical fibre vibration sensor is explained. It is shown how different sensing systems use the phase of Rayleigh backscattered light to map vibrations along tens of kilometres of optical fibre. The sensing setup of the DAS system developed at the Optoelectronics Research Centre (ORC) and its operation is discussed. Finally, the results obtained from a number of field trials such as submarine-cable condition monitoring and traffic monitoring is presented.
Keynote Forum
W C H Choy
The University of Hong Kong, Hong Kong
Keynote: Distinct multi-physical effects of plasmonic metal nanostructures for high performance optoelectronic devices
Biography:
W C H Choy is a full Professor in the Department of EEE, HKU. His research interests cover organic/inorganic optoelectronic devices, plasmonic structures, metal oxides, and nanomaterial devices. He has published more than 180 peer-reviewed papers, several book chapters, patents, and edited one book. He was recognized as top 1% of most-cited scientists in Thomson Reuter’s Essential Science Indicators from 2014 to 2017. He has served as Member of Engineering panels of Hong Kong Research Grant Council, Editorial Board Member for Nature Publishing Group on Scientific Reports, Wiley on Solar RRL and Institute of Physics on J Physics D, Senior Editor of IEEE Photonics Journal, Topical Editor of OSA Journal of the Optical Society of America B, and Guest Editor of OSA Journal of Photonic Research, and Journal of Optical Quantum Electronics. He is an elected fellow of OSA.
Abstract:
The remarkable enhancement of plasmon -optical and -electrical effects by metal nanostructures will be described in detail for high performance optoelectronic devices such as light emitting diodes and solar cells. Taking plasmonic organic solar cell as an example, the power conversion efficiency can reach over 10.5%. The plasmon-optical effects have been utilized to optically enhance active layer absorption in organic solar cells (OSCs). The exploited plasmonic resonances of metal nanomaterials are typically from the fundamental dipole/high-order modes with narrow spectral widths for regional OSC absorption improvement. The conventional broadband absorption enhancement (using plasmonic effects) needs linear-superposition of plasmonic resonances. Moreover, with appropriate incorporation of metal nanostructures into the multilayered OSCs, plasmon-electrical effects can be introduced to improve the electrical properties of carrier transport layer and eliminate the space charge limit of organic active layer. In this talk, we will describe the details of the plasmon -optical and -electrical effects by introducing metal nanostructures on different layer of OSCs. Recently, through strategic incorporation of gold nanostars (Au NSs) in between hole transport layer (HTL) and active layer, the excited plasmonic asymmetric modes offer a new approach toward broadband enhancement. Remarkably, the improvement can be explained by energy transfer of plasmonic asymmetric modes of Au NS. Moreover, Au NSs simultaneously deliver plasmon-electrical effects which shorten transport path length of the typically low-mobility holes and lengthen that of high-mobility electrons for better balanced carrier collection. Meanwhile, the resistance of HTL is reduced by Au NSs. Consequently, PCE of 10.5% has been achieved through cooperatively plasmon-optical and -electrical effects of Au NSs. With the understanding of the multi-physical (optical and electrical) effects, we will also demonstrate significant performance improvement of plasmonic nanostructures for organic light emitting diode applications.
- Photonics | Optical Imaging and Sensing | Optical Fiber | Lasers and Nonlinear Optics | Laser Systems | Quantum Optics | Nano and Qauntum Sciences
Location: Meeting Room- (Sylt 1-2)
Chair
Bruno Wacogne
FEMTO-ST Institute, France
Co-Chair
Günter Nimtz
Universität zu Köln, Germany
Session Introduction
Albrecht Lindinger
Freie Universität Berlin, Germany
Title: Shaped laser pulses after optical fibers for selective multiphoton excitation of biomolecules
Time : 11:15-11:40
Biography:
Albrecht Lindinger has earned his PhD on helium droplet spectroscopy in Göttingen in the group of Prof. Dr. J P Toennies and took his Postdoc term in Berkeley in the group of Prof. Dr. D Neumark. He received his habilitation in the field of coherent control at the Freie Universität Berlin in the group of Prof. Dr. L Wöste and is now a Lecturer in the Institute of Experimental Physics at the Freie Universität Berlin. He has published 80 peer-reviewed papers in reputed journals. His main scientific interests are laser optics, coherent control, and biophotonics.
Abstract:
Recently, ultrashort laser pulses were increasingly used for multiphoton excited imaging in biological samples. Fluorescent molecules were employed to distinguish between tissue structures, and a high contrast is favourable for microscopic imaging. Thereto, laser pulse shaping provides a powerful tool by tailoring the pulses such that two species may selectively be excited. In particular, tailoring of laser pulses is applied to exploit intrapulse interference effects in multiphoton excited fluorescence. Furthermore, pulse shaping is successfully used to control photo-induced processes. Novel pulse shaping schemes for simultaneous phase, amplitude, and polarization control were designed in recent years, and a parametric subpulse encoding was developed. Thereby, physically intuitive parameters like chirps and polarization states can be controlled. This yields new perspectives of utilizing all properties of the light field in the pulse modulation. This contribution describes pulse shaping methods for improved multiphoton excited fluorescence contrast after transmitting a nanostructured kagome fiber. The distortions due to the optical fiber properties are precompensated to receive predefined shaped pulses at the distal end of the fiber. Special antisymmetric phase functions are employed for scans of the multiphoton excitation fluorescence. Application of phase-shaped pulses for imaging contrast enhancement is demonstrated for the autofluorescing vitamins A and B2. Moreover, particularly phase and polarization tailored pulses are employed to optimally excite one dye in one polarization direction and simultaneously the other dye in the other polarization direction. The presented method has a high potential for endoscopic applications due to the unique kagome fiber properties for imaging of endogenous fluorophores.
Seoyong Shin
Myongji University, South Korea
Title: Design of Fresnel lens for uniform LED lighting
Time : 11:40-12:05
Biography:
Seoyong Shin has been in the Department of Information and Communication Engineering at Myongji University since 1994. He has published more than 40 SCI and SCI-E papers so far. He started research in the field of optical communication, especially optical active functional modules including wavelength converter, optical buffers for WDM network, and dynamically gain-controlled EDFA for WDM networks. His research has moved on to solar energy related topics since 2007 where he can apply his prepared knowledge of optics and optical fibers. His main interested topics are optical fiber based daylighting system and concentrator photovoltaic systems.
Abstract:
A uniform light diffuser for a light-emitting diode (LED) light source is an essential device widely used in lighting engineering. We present a linear Fresnel lens design for LED uniform illumination applications. The LED source is an array of LED. An array of collimating lens is applied to collimate output from the LED array. Two linear Fresnel lenses are used to redistribute the collimated beam along two dimensions in the illumination area. Collimating lens and linear Fresnel lens surfaces are calculated by geometrical optics and non-imaging optics. A collimating lens has the simple structure of a plano-convex lens. The linear Fresnel lens is constructed by many grooves. The collimated beam output from the collimating lens array is divided into many fragments corresponding to the number of Fresnel lens grooves. Each fragment is refracted by a groove and distributed over the illumination area, so that total beam can be distributed to the illumination target uniformly. The designed system was modeled and simulated with LightTools software to explore the optical performance. The simulation results indicate that 82% optical efficiency was achieved at a uniformity of 76.9% for the proposed system. The simulation of the performance of our design for practical purposes, such as indoor and street lighting, and the comparison with a conventional light source were conducted. The simulation results show that this design has a compact structure, a high optical efficiency, and a good uniform distribution. Some consideration on the energy saving and optical performance are discussed by comparison with other typical light sources. The results show that our proposed LED lighting system is a strong candidate for low cost, energy saving for indoor and outdoor lighting applications.
Bruno Wacogne
FEMTO-ST Institute, France
Title: Toward calibration free ion sensing: A focus on fiber optic fluorescence pH sensor
Time : 12:05-12:30
Biography:
Bruno Wacogne is a CNRS Research Director at the FEMTO-ST Institute (UMR CNRS 6174) where he is leading the transversal axis Biom’@x concerning Sciences and Technologies for a Translational Medicine. He is also the Technological Coordinator of the Clinical Investigation Center of Besançon University Hospital (INSERM CIC1431) where he is leading the Microsystems and Biological Qualification team. His research interests are micro technologies, optics, translational research, biological qualification and immune-combined medical devices. He is the author or co-author of nearly 200 communications and 10 patents.
Abstract:
This work is part of the development of a fiber optic fluorescence pH sensor for in vivo measurement. The sensor uses pH dependent molecules grafted at the cleaved-end of an optical fiber. Molecules like SNARF®, allow measuring pH by calculating the ratio of the emitted fluorescence at two distinct wavelengths. This ratiometric technique is not calibration free and molecule manufacturers advise users to perform a pre-calibration using the acidic and basic endpoints of titration respectively. This calibration procedure requires controlling very accurately the experimental conditions and is time consuming for clinical applications. In this conference, we present methods to simplify and even avoid calibration procedures. We first show that calibration can be performed without controlling the experimental conditions. Then, we present a complete mathematical description of the pH-dependent fluorescence properties of SNARF®. Once modelled, the whole shape of the fluorescence spectrum can be described using only one parameter, thus allowing a calibration free pH measurement using simple and rapid numerical fitting. However, SNARF® exhibit some drawbacks (extremely fragile and low quantum efficiency). Conversely, fluorescein is a robust and high quantum efficiency pH dependent fluorescent molecule. Up to now, fluorescein had never been considered for a potential calibration free pH measurement because of its single emission peaks. It was considered that pH can only be measured by normalizing the fluorescence intensity measured at unknown pH with the intensity measured at high pH value. In this conference, we show that numerical treatments of the emitted fluorescein spectra allow measuring the pH without calibration.
Kyuman Cho
Sogang University, South Korea
Title: A high performance I/Q-interferometer using a polarizing beam displace and its application to resolution refractive index sensor
Time : 12:30-12:55
Biography:
Kyuman Cho has expertise in precision measurements using various interferometer schemes. He has been performing extensive researches in developing interferometric approaches in many high sensitivity applications sensors such as a scanning microscopy for characterization of optical properties of surfaces and materials, readout sensor for reaction monitoring on a biochip, long range vibrometer, and many other applications. He has been also working on diagnostics of the magnetically confined plasma in KSTAR, the fusion reactor project in South Korea. He has been a Professor of Physics, Sogang University since 1992. He has been a Visiting Professor in the Department of Electrical and Computer Engineering, University of Maryland, USA, Institute of Cosmic Ray and Radiation, University of Tokyo, Japan. He is a Collaborator for KAGRA, a cryogenic gravitational wave antenna, being built in Kamioka, Japan.
Abstract:
It has been shown that an I/Q-interferometer can be used for measuring refractive index of a liquid or liquid mixture flowing through fluidic channels. We recently developed a new I/Q-interferometer which may be ideal for fluidic channel measurements because of its simple optical arrangement and capability of adjusting beam separation. A schematic of optical arrangement is shown in the image. The polarizing beam displace (PBD) is a modified polarizing beam splitter for which the two output faces are angle polished to make two orthogonally polarized output beams from the polarizing beam splitter parallel to each other. The output beams are circularly polarized with opposite handedness are making double pass through the corresponding liquids in the fluidic channels by use of the mirror coated on the backside of the fluidic channel. The phase difference and amplitude difference between the returning two beams are induced by the corresponding liquids in the fluidic channels. After making double pass in the quarter-wave plate, the plane of polarization of the two beams are rotated by 90o and combined at the PBD. The combined beam is output through the remaining port of the PBD and sent to the I/Q-demodulator. The phase difference and amplitude difference are measured simultaneously by using either a homodyne or a heterodyne I/Q-demodulator. We had shown that a heterodyne I/Q-interferometer with more complicated optical arrangement can measure 1´10-8 refractive index difference between liquids in the reference and probe channel. Our new arrangement can provide a better sensitivity because not only it has a fewer number of optical components but also the system can be integrated into a small size device. In the sample channel, reference fluid and sample fluids can be flown through an alternating way. Phase measurements across consecutive liquid flow and unwrapping measured phases allow a precision measurement of refractive index difference between two liquids.
David Abookasis
Ariel University, Israel
Title: Simultaneous measurements of absorption, scattering, and refractive index parameters of mouse brain tissue by NIR structured illumination and models approximation
Time : 12:55-13:20
Biography:
Abookasis is a faculty member in the Department of Electrical Engineering at Ariel University, Israel where is serve also as the head of the medical engineering program. His main research focus on optical diagnosis and therapy in neurological diseases and brain trauma. Dr. Abookasis possesses a multi-disciplinary background combining engineering, optics, biomedical optics, medical instrumentations, and neurology
Abstract:
Successful derivation of biological tissue optical parameters such as absorption, reduced scattering, and refractive index coefficients can serve a range of downstream diagnostic and research applications. A practical measurement procedure for determination of these intrinsic parameters in the near-infrared (NIR) spectral range is suggested. Structured light patterns at low and high spatial frequencies of six wavelengths ranging between 690 and 970 nm were projected onto biological tissue surface. In the offline analysis pipeline, four different approaches based on Maxwell equations and Kramers–Kronig relations were applied on the recorded images at each wavelength to resolve tissue parameters. For the wavelength-dependent properties presentation, Mie approximation and dispersion models were utilized. Our approach, validated in mouse (n=5) experience heatstroke condition, show variations from baseline measurements in the intrinsic brain properties following injury which in turn reflect brain hemodynamics and morphological variations. Overall, this work demonstrates a proof-of-concept of the proposed method which we believe will be beneficial to the biophotonics community.
Günter Nimtz
University of Cologne, Germany
Title: On the universal tunneling time
Time : 14:10-14:35
Biography:
Günter Nimtz has completed his PhD in the year 1969 from Vienna University. At that time he studied semiconductor physics and discovered the negative differential resistivity of hot carriers in Tellurium. Later he investigated the electromagnetic interaction of biophysical systems and spent much time with the faster than light propagation of tunneling microwave signals. He has published more than 200 papers and several books in reputed journals. He has several patents, which for example are applied in electromagnetic compatibility chambers and in the preparation of rare earth metals. He is a retired Professor of Physics at the University of Cologne.
Abstract:
These days the tunneling process is for instance applied in fiber optic communications and even in cars as windscreen wiper. Tunneling is a universal process in all fields. One property of tunneling is of special interest: the time the wave packet spends inside the barrier. Recent investigations have been carried out in electromagnetic and elastic fields. The tunneling and barrier interaction times of neutrons have been previously studied. Here we show that the neutron interaction time with barriers corresponds to the universal tunneling time of wave mechanics, which was formerly observed with elastic, electromagnetic, and electron waves. The universal tunneling time seems to also hold for neutrons. Such an adequate general wave mechanical behavior was conjectured by Brillouin. Remarkably, wave mechanical effects and even virtual particles hold from the microcosmos up to the macrocosm.
Jana Soumendu
Thapar Institute of Engineering and Technology, India
Title: Dissipative soliton in VCSEL
Time : 14:35-15:00
Biography:
Jana Soumendu obtained his MSc degree in 2001 from Vidyasagar University, India and PhD in 2008 from Birla Institute of Technology (BIT), Mesra, India. He worked with the CNQO group at University of Strathclyde, Glasgow, UK, during his BOYSCAST Postdoctoral Fellowship tenure. Currently, he is an Associate Professor at School of Physics and Materials Science, Thapar Institute of Engineering and Technology, Patiala, India. His research interest includes nonlinear optics, photonics and nonlinear dynamics. He published nearly fifty research papers in peer reviewed international journals and conference proceedings. He published a book entitled “Nonlinear Pulse and Beam Propagation”. He is a Referee of many internationally renowned research journals. He is also a Visvesvaraya Young Faculty Research Fellow.
Abstract:
Dissipative soliton (DS) are localized structure e.g., wave and pulse in lossy systems. Such DS has been excited in form of bright spot on dark background in vertical cavity surface emitting laser (VCSEL) based models in conjugation of frequency selective feedback (FSF). These DS are popularly referred as cavity soliton (CS). DS in cavity or cavity soliton (CS) exhibits intriguing dynamics, which is supported by the large area of VCSEL. The parametric space for stabilization and control of CS has been identified. The role of system randomness, an unavoidable feature that arises from multiple parameters, has been explored. Since CS dynamics is very sensitive to the any inhomogeneity present in the system we explore the possibility to use it to design an alternate microscopy, namely, ‘soliton force microscope’. However, the size of the CS is pivotal to decide the resolution of the microscope. Emphasis has given to reduce the CS spot size. Also, we searched for the systems which can be scanned with the existing size of CS. The result may lead to design a ‘soliton force microscope’ primarily with moderate resolution. A sustained CS or CS cluster requires a stable background. We found two distinct types of CS on a stable background. This may lead to realization of three-level logic. Besides, CS may be exploited to design memory devices. An essential feature of CS is the presence of their bistability character, which can be better realized by introducing a saturable absorbing material or saturable absorber (SA) in the cavity. Generally semiconductor saturable absorber mirrors are used. We explored the potential of graphene and other 2D materials as SA in VCSEL. Particularly, graphene eases the CS generation significantly as well as upgrades the CS system as an efficient biomedical sensor. The future line of investigation is highlighted.
Aleksandr Tarasov
Laseroptek Ltd., South Korea
Title: Scaling of sub-nanosecond gain-switched lasers to subjoule energy level
Time : 15:00-15:25
Biography:
Aleksandr Tarasov worked at Vavilov State Optical Institute, Leningrad, USSR from 1972 to 1989. He received there PhD degree in 1984. From 1989 to 2000 he worked at the Institute of Nuclear Problems, Minsk, Belarus. Since 2002 he is working at Laseroptek, South Korea, as Principal Research Scientist. He is a Recipient of 1982 USSR Leninski Komsomol Prize. He has published more than 70 papers at USSR and international scientific journals. He is a Member of Optical Society of America.
Abstract:
In 1989-2001 J Zayhowski with collaborators from MIT investigated simple alternative to mode-locking method for generation of subnanosecond pulses in Nd: YAG, Ti: Sapphire and some other laser crystals. They developed a batch of gain-switched microchip lasers, having cavity length less than 10 mm, and obtain generation of single pulses in near IR range with energy ~10-5 J and duration 300-900 ps, using for pumping pulsed subnanosecond radiation of other lasers. No any additional results related to this problem were found in literature until 2018. Last year’s laser medical market shows considerable demand in lasers for tattoo removal. Such lasers must possess relatively high pulse energy level, ~0.1 J or larger, and produce subnanosecond pulses at 1…10 Hz. Following to this demand, with the goal to develop budget tattoo removal lasers, we investigated high energy gain-switched generation of Ti: Sapphire crystals in short laser cavity, using for pumping pulses with nanosecond duration instead subnanosecond, because available pulse energy and laser damage threshold for nanosecond pulses are larger. Using second harmonic of multimode Q-switched Nd: YAG laser with pulse duration ~4 ns, we obtain generation at central wavelength 790 nm with maximum pulse energy 0.3 J, available pulse duration from 400 to 1000 ps and repetition rate from 1 to 10 Hz. At present time it is highest level of characteristics, available from tattoo removal lasers, radiating at 700-800 nm. In our presentation we shall consider the main physical factors, that restrict energy and minimum pulse duration, and solutions, which allow reduction of the influence of these factors and further improvement of laser performance.
Ruiya Li
Wuhan University of Technology, China
Title: Fiber Bragg Grating (FBG) sensing technology and its application in thermal errors monitoring of CNC machine tools
Time : 15:40-16:05
Biography:
Yuegang Tan--(Ruiya Li) is currently a Professor with the School of Mechanical and Electronic Engineering, Wuhan University of Technology, China. He received his PhD from Wuhan University of Technology in 2005. He has presided over many important scientific projects, such as National Natural Science Foundation of China, 863 Program of China, etc. He has authored or coauthored more than 90 journal and conference publications, 7 granted Chinese invention patent, and has published 2 academic books. Currently his research interests include optical fiber sensing technology, thermal errors of heavy-duty CNC machine tools, security of large-scale rotating machinery, structural health monitoring (SHM) and fault diagnosis of modern mechanical equipment, and underactuated robot technology. Mr. Ruiya Li is his PhD candidate, who is currently studying as a visiting research student with supervisor Prof. Duc Truong Pham in University of Birmingham, UK.
Abstract:
For a long time, fiber Bragg grating (FBG) based sensors were intensively studied for application in civil engineering structure, like bridges, dams, etc. Recently, due to the advantages of small volume, light weight, anti-electromagnetic interference, anti-oil corrosion, and multiple measuring points in one optical fiber, FBG-based sensors have attracted lots of interests and been widely investigated by researchers and engineers in industrial filed. Our research focuses on dynamical monitoring and diagnoses of mechanical systems based on distributed fiber Bragg grating sensors. The FBG-based sensors we developed for mechanical equipment (large steam turbine, aeroengine, large crane, heavy-duty CNC (computer numerical control) machine tools, etc.) involves the measurement of temperature, strain, force, pressure, and accelerator. Thermal error monitoring technology is the key technological support to solve the thermal error problem of heavy-duty CNC machine tools. FBG temperature sensors were utilized to detect the temperature field of main heat sources and the body structure in heavy-duty CNC machine tools to study the thermal characteristics of main heat sources and to establish the thermal error prediction model. Meanwhile, based on the advantage of multiple strain measuring points in one optical fiber, FBG-based strain sensors were studied and used to measure the thermal deformation of structural components (gantry beam, column and base) of the heavy-duty CNC machine tools using the integral relationship between the strain and deformation.
Cheng Yen Chien
Graduate Institute of Electronics Engineering – NTU, Taiwan
Title: Defect reduction of GaN growing on dome-shaped patterned - sapphire substrates
Time : 16:05-16:30
Biography:
Cheng Yen Chien is PhD in Graduate Institute of Electronics Engineering, National Taiwan University. He has his expertise in electronic device, optoelectronics, nanotechnology, electron-beam lithography and application and III-V material. He demonstrated a new pattern design based on sapphire that effectively reduced dislocation density on surface GaN. The foundation is based on variety of GaN stress and strain which also modulates growth rate with GaN by MOCVD. This approach is responsive to all stakeholders and has a different way of focusing.
Abstract:
Defect reduction is always an important topic for the researches of epitaxy improvement. Commercial dome-shaped patterned-sapphire substrates (CDPSS) had been designed to tackle this problem during the epitaxy of gallium nitride (GaN), and they did reduce the density of defect considerably. In order to reveal the veiled mechanism of defect reduction, we had executed Raman scattering and x-ray diffraction (XRD) measurements on various samples with different growth time to verify the behavior of defects during epitaxy 1. The results of etch pits density (EPD) had been included in figure 2, too. All the measurements show a trend of rapidly decreasing rate initially, but become smooth after 20 minutes. The reason could be figured out from the TEM cross section images. The empty spaces surrounding the sidewall of slope indicate that the growing rate here is so slow that the lateral growth takes place. When the accumulated strain reaches to a critical level, it forces dislocations to turn toward the interface to release the strain, as the red lines and yellow arrows indicate in the left part of figure 3. These lateral dislocations can block other up growing dislocations under them; therefore the defects reduce rapidly. When the growth of GaN reaches the summit of domes (about 20 minutes), only few thread dislocations (TDs) are left. With the continuous growing of GaN, these TDs could join other TDs as the yellow arrow indicated in the right part of figure 3, and the total TDs reduce gradually further. With knowing of the mechanism of defect reduction, further investigations can be designed. The performance of devices with fairly low defect density can be improved greatly. Even defect free region also be expected. It will improve the performance of electronic device and optoelectronic device. And we believe that not only feasible for GaN, but also for other III-V materials.
Bhaskar Kanseri
Indian Institute of Technology, Delhi, India
Title: Experimental studies on bright quantum states of light
Time : 16:30-16:55
Biography:
Bhaskar Kanseri is currently working as an Assistant Professor at Indian Institute of Technology Delhi. He leads a research group namely Experimental Quantum Interferometry and Polarization (EQUIP). His research interests include experimental quantum optics, quantum information science (quantum cryptography and quantum computing), non-linear optics, and in coherence and polarization optics. He is a Member of several optical societies including, Optical Society of America, SPIE, Indian Laser Association and Optical Society of India.
Abstract:
Bright quantum states of light are progressively a subject of intense research owing to the fact that these states can provide much stronger interactions with matter and with each other than the fait (microscopic) stets of light. As they contain large numbers of photons, they resemble with classical systems. Thus it becomes essential to investigate to what extent such states exhibit “quantumness”. Microscopic Bell states, which are four modes squeezed vacuum states, are one such bright system containing typically 106 photons per pulse. We wish to implement a method namely ‘three-dimensional quantum polarization tomography’ for characterization of polarization and squeezing features of these states. In addition, we wish to explore the non-classical correlations and entanglement features of these states. In recent years, these bright photon states have found potential applications in fundamental tests, gravitational wave detection, quantum storage, and absolute measurement of detectors’ quantum efficiency. The polarization features of macroscopic Bell states are characterized using the method of quantum polarization tomography, which utilizes three-dimensional inverse radon transform to reconstruct the polarization quasi-probability distribution function of a state from the probability distributions measured for various Stokes observables. The reconstructed distributions obtained for these states are compared with those obtained for a coherent state with the same mean photon number. The results demonstrate squeezing in one or more Stokes observables (polarization squeezing). In addition, in these states, photon-number correlation measurements are performed using a standard Bell-test setup, and explicit quantum correlations are observed for conjugate polarization-frequency modes, as shown in the figure 1. We also test the entanglement witnesses for these states and it is observed that these states violate of the separability criteria, inferring that all these bright quantum states are polarization entangled.
- Young Researcher Forum
Location: Meeting Room- (Sylt 1-2)
Chair
Andrei Ivanov
ITMO University, Russia
Session Introduction
Cheng Yan Gao
Beijing Normal University, China
Title: Multi-photon self-error-correction hyperentanglement distribution over arbitrary collective-noise channels
Biography:
Cheng Yan Gao is a first year PhD candidate in Department of Physics at Beijing Normal University, P R China. She majors in quantum optics and quantum communication and she is interested in quantum communication theory, quantum error correction and quantum repeater. In 2017, she published two papers on quantum error correction as the first author; one was published in Quantum Information Processing and the other was published in the Journal of Physics B: Atomic, Molecular and Optical Physics.
Abstract:
Entanglement, the quintessential quantum correlations between two quantum systems, has been widely used in quantum communication over the past decades. The distribution of entanglement is a crucial module in many quantum information processing protocols. However, in a practical transmission, entanglement is easily influenced by the noise in quantum channel, which will turn the maximally entangled state into a mixed state. To overcome the influence from channel noise, we present a self-error-correction hyperentanglement distribution scheme for three-photon system in both spatial and polarization degrees of freedom with linear optical elements and Pockel cells. In our scheme, the three-photon system is initially prepared in a spatial-polarization hyperentangled state and subsequently encoded into time-bin entangled state which is rather robust and hard to be affected by the channel noise. After transmitting over the noisy channels, the time-bin entanglement is transformed into spatial-polarization hyperentanglement. Thus, with our scheme, the parties in quantum communication can share maximally hyperentangled states in spatial and polarized degrees of freedom with the success probability of 100% in principle.
Christoph Zesch
University of Rome Tor Vergata, Italy
Title: Stimulated Raman scattering in crystals and applications
Biography:
Christoph Zesch is a PhD student at the University of Rome Tor Vergata and works as a Scientific Employee at the Technical University of Applied Sciences Wildau and the Technical University Berlin. He received the Master of Engineering at the Technical University of Applied Sciences Wildau in 2017. His expertise is in Nonlinear Optics and Laser Spectroscopy especially in stimulated Raman scattering and solid state Raman lasers and amplifiers.
Abstract:
Stimulated Raman scattering (SRS) is a third-order nonlinear optical effect and has been observed in more than 120 crystals which we pumped using pulsed Nd:YAG lasers at 1064 nm, 532 nm or 355 nm wavelength. More than 2000 SRS lines have been observed covering the spectral region from 300 nm to 3500 nm. Frequency conversion by SRS has been established as a versatile method to produce laser radiation at specific wavelengths which cannot be obtained with conventional laser materials. Prominent Raman crystals include BaNO3 and other nitrates, KGW and other tungstates, YVO4 and other vanadates as well as diamond. These crystals exhibit lattice vibrations with wave numbers from 80 cm-1 to 3150 cm-1 shifting the incident laser wavelength to higher or lower values. Recently, we observed SRS in the natural crystal spodumene (α-LiAlSi2O6) and in LuAlO3. Moreover, generation of wide frequency combs via SRS, with equidistant lines in the frequency domain, has opened a new path of research on ultrashort pulse synthesis. Efficient amplification of a specific Raman frequency component is possible by placing the Raman crystal into a frequency-selective optical resonator. This configuration strongly decreases the SRS threshold and results in low-divergent laser radiation at the desired wavelength. Raman lasers can be used in many applications, e.g. differential absorption LIDAR systems (DIAL, light detection and ranging) to detect trace gases like carbon dioxide or ozone. Following this approach, a substantial extension of the spectral coverage by solid-state lasers has been achieved over the last five decades. Various pumping schemes and resonator designs have been investigated focusing on good conversion efficiency, high spatial beam quality and high pulse energy of the output beam.
Wei Jaing
Beijing Normal University, China
Title: Non-Markovian entanglement dynamics of continuous measurement feedback open quantum system in structured bath
Biography:
Wei Jaing is a Doctoral student of Physics Department, Beijing Normal University. He has graduated from Central South University and has got a Bachelor's degree of Electronic Information Engineering. His research field is non-Markovian effect in quantum optics.
Abstract:
In the past two decades, entanglement has attracted much attention continuously for its potential use as the key resource of quantum computation and quantum information. Due to decoherence of a system coupling to its environment or bath, entanglement degradation is unavoidable. In this work we investigate the entanglement dynamics of two two-state quantum systems coupling to a Bosonic mode and a common structured bath. Here the Bosonic mode, which is resonantly driven by a classical filed and heavily damped by a broadband reservoir, acts as a probe resonator for the use of continuous quantum measurement feedback, and the bath has one of three different structures characterized by the Ohmic types of spectral densities. We proceed by using hierarchical equations of motion (HEOM) approach. We present the master equation of the reduced density matrix for the system investigated and, accordingly, the HEOM for auxiliary operators. The HEOM calculation shows that the quantum measurement feedback plays a positive role in the entanglement generation, and the non-Markovian effect of the bath could greatly enhances this action, increasing the entanglement by 50% in the case of, for example, the Ohmic bath. We reveal in detail the dependence of the scheme performance on the spectral density parameters, the temperature of the bath, and the measurement feedback. The numerical results are obtained with the HEOM truncated at the 3rd order, which are equal to those obtained with the 6th order perturbation theory.
Ming Li
Beijing Normal University, China
Title: Entangling two distant high-Q microwave transmission lines assisted by a resonator terminated with SQUIDs
Biography:
Ming Li is a first year PhD candidate from Department of Physics in Beijing Normal University (BNU) Beijing, China. His major is quantum optics and he is interested in the field of superconducting circuit quantum electromagnetic dynamics and its applications in quantum computation. He has conducted some preliminary research studies on the dynamical Casimir effect induced by fast-tuned boundary conditions, which can be easily implemented in superconducting circuit platform.
Abstract:
We propose a multi-resonator superconducting circuit to create the entanglement state between resonators which are specially arranged. One high-frequency resonator is placed in the middle working as a quantum bus and has two superconducting quantum interference device (SQUID) ends which function as effective boundaries. The other two resonators are vertically placed on sides and the magnetic flux created by these two resonators modulates the boundaries of the middle resonator, which in turn creates a nonlinear interaction between resonators. This coupling introduces opto-mechanical type Hamiltonian terms which can be used to generate a Bell state between two high-quality resonators with fidelity of 99.2% for practical parameters. The strength of the opto-mechanical terms is tunable, which meets the cure to the crosstalk in quantum computing and allows the possibility of large-scale integration of resonators and all-resonator quantum computing.
Dun Liu
Chinese Academy of Sciences, China
Title: Effect of the number of primary lens level on the MTF of diffractive imaging system
Biography:
Dun Liu is a PhD student at the University of Chinese Academy of Sciences. In 2013, he received his Bachelor's degree at Wuhan University. He has been conducting the research of diffractive telescope technology at the Institute of Optics and Electronics, Chinese Academy of Sciences, from 2013 till now. His current research interests include optical design, stray light analysis and test.
Abstract:
For space telescopes with large apertures and light-weight, phase-type Fresnel lenses has been proposed to replace the primary mirror. However, the diffraction efficiency of 2-level phase-type Fresnel lenses fabricated by binary optics technology can only achieve 40.5% and 81% for 4-level. The non design orders diffractive light may affect the modulation transfer function (MTF) of diffractive imaging system. In this paper, the wave propagation method was used to simulate the propagation of diffractive light. By coherent superposition of finite diffractive waves, the point spread function (PSF) was calculated at several signal wavelength which evenly covers the spectral range of system. The Fourier transform of the PSF was MTF. The MTFs of an 80 mm diffractive imaging system were analyzed when the number of Fresnel primary lens' level was 2, 4 and 8. The MTF decreased at low frequency with 2-level Fresnel primary lens and the biggest decrease was 6.6%. The deviation from the design value is less than 0.5% when the level is 4 and 8. The results show that the effect of diffractive stray light on the MTF of the system decreases with the increase of the number of level. During the analysis, we found that only the incident light illuminating the primary lens’s central area can directly attach the image plane by non design diffractive orders. So, a hybrid-level Fresnel lens was put forward to reduce the effect of diffractive stray light. The MTF increased apparently after optimized and was close to the design value.
Peng Liang Guo
Beijing Normal University, China
Title: Entanglement state transmission without calibrate reference frame
Biography:
Peng Liang Guo is a second year PhD student in Department of Physics at Beijing Normal University, P R China. Her research direction is Quantum Optics. She focuses on quantum state error rejection transmission and experimental technologies in quantum information process.
Abstract:
Entanglement is a very important quantum resource in quantum communication, which guarantees the security of communication and has many important applications in quantum communication, such as quantum key distribution, quantum teleportation, and quantum dense coding. We demonstrated a theoretical entanglement state transmission scheme using time-bin operations. The scheme is robust against the instability of the reference frame between two parties, and can be extended to Greenberger-Horne-Zeilinger (GHZ) states without shared reference frame (SRF). When Pockels cells are used in the scheme, the success probability can be improved to 100%. The entanglement states are shared between many parties with no shared reference frame, which is significant for quantum communication and the construction of a long-distance communication networks.
Shuang Wu
Beijing Normal University, China
Title: Young’s double-slit interference with two-color biphotons
Biography:
Shuang Wu obtained his BS degree at MinZu University in China in 2014. Now he is a PhD student in Department of Physics, Beijing Normal University, China. His current research focuses on quantum imaging.
Abstract:
In classical optics, Young’s double-slit experiment with colored coherent light gives rise to individual interference fringes for each light frequency, referring to single-photon interference. However, two- photon double-slit interference has been widely studied only for wavelength-degenerate biphoton, known as subwavelength quantum lithography. In this work, we report double-slit interference experiments with two-color biphoton. Different from the degenerate case, the experimental results depend on the measurement methods. From a two-axis coincidence measurement pattern we can extract complete interference information about two colors. The conceptual model provides an intuitional picture of the in-phase and out-of-phase photon correlations and a complete quantum understanding about the which-path information of two colored photons.
Shan Shan Chen
Beijing Normal University, China
Title: Universal single-qubit non-adiabatic holonomic quantum gates in optomechanical systems
Biography:
Shan Shan Chen is a graduate student in grade two of Physics Department, Beijing Normal University. Her research field is quantum information and quantum computation.
Abstract:
The non-adiabatic holonomic quantum computation (NHQC) attracts widespread attention in recent years because of its advantage of fast and robustness. It has been realized based on physical systems including superconducting circuits, NMR, and nitrogen-vacancy center in diamond. In this work we propose the first scheme to achieve the NHQC based on an optomechanical system (OS). This OS is composed of two optical cavities coupling to a mechanical oscillator as shown by figure 1. Our NHQC includes single-qubit noncommute NOT gate, phase gate and Hadamard gate, which are obtained in the computational basis of the single excited states of the OS. With these universal quantum gates, we can also achieve the quantum state transfer and the entanglement generation between two cavity-modes. We discuss the corresponding experimental parameters and the fidelity of the scheme with imperfection by numerical simulation. Our scheme is of all the good properties of the NHQC based on a quantum system, such as the built-in noise-resilience, faster operation, less decoherence and non-requirement for the resource and time to remove the dynamical phases. It provides a prototype of quantum gates realized with the mechanical motion degree of freedom. OSs can serve as important platforms for generating various quantum effects in the systems ranging from quantum to classical ones, and our scheme is such an example in quantum computation and quantum information processing.
- Latest Technologies in Photonics and Lasers | Applied Industrial Optics | Industrial Applications of Laser and Photonics | Optical Technologies
Location: Meeting Room- (Sylt 1-2)
Chair
Andrei Ivanov
ITMO University, Russia
Co-Chair
David Abookasis
Ariel University, Israel
Session Introduction
Rosa Ana Perez Herrera
Universidad Pública de Navarra, Spain
Title: Latest technologies in optical fiber lasers for sensing applications
Biography:
Rosa Ana Perez Herrera received the Telecommunications Engineering degree from the University of Cantabria, Spain, in 2004. In 2005 she joined the Optical Communications Group at the Department of Electrical and Electronic Engineering of the Public University of Navarra (Pamplona, Spain). In 2010 she obtained her PhD degree from the Public University of Navarra, Spain. Her research interests are in Raman amplifiers, erbium-doped amplifiers, fiber-optic sensors and multiplexing architectures. She has co-authored more than 70 papers, presented in conferences and scientific journals.
Abstract:
As it is well known, optical fiber lasers can be used as sensor elements on their own, which offer new possibilities for developing high-performance sensors with compact size when needed and reduced complexity. A number of distributed and point optical fiber lasers can be developed for different sensing applications depending on the technology used to generate the laser and also depending on the physical or chemical parameter under evaluation. On the other hand, optical fiber laser sensors are some of the most reliable and robust laser systems. Taking care of the design and manufacturing process required to guarantee a high level of reliability, inhospitable environments can be easily monitored even when they operate in such harsh conditions such as sensing in high-voltage or high-power machinery, or in explosive environments. Also, the increasing interest about structural health monitoring systems has helped to raise the development of novel optical fiber laser technologies for sensing applications. More and more lately developed fiber technologies bring a superior performance to fiber-optic sensing networks. Tunable FBG-based laser interrogators implemented by several kinds of fiber laser systems, such as novel Fourier domain mode locking fiber lasers, or those based on random lasers implemented by means of Raman amplification or even erbium doped fiber amplifiers, have been demonstrated, both theoretical and experimentally, to be a good option to develop new optical fiber laser for sensing applications. In this work, the uses of some advanced photonic technologies that include fiber laser technologies, among others, for fiber sensing applications are presented.
A Merten
Fraunhofer IPMS, Germany
Title: Miniaturized tunable QCL - lightsource for MID-infrared spectroscopy
Biography:
A Merten received his Diploma-degree in Physics from Friedrich-Schiller-University Jena (Germany) in 2003. Following he was a PhD student at Institute of Environmental Physics in Heidelberg and worked on differential optical absorption spectroscopy (DOAS) of atmospheric trace gases. Afterwards he joined the Institute of Applied Photo Physics (IAPP) at the Technical University in Dresden and worked on the optical simulation and characterization of thin film organic solar cells. He joined the Fraunhofer Institute for Photonic Microsystems (IPMS) in 2012 and is working on the opto-mechanical system design of miniaturized projectors and 3D-LIDAR cams involving MEMS scanners as well on the optical characterization of MEMS based scanner mirrors.
Abstract:
Broadband tuning of MIR-infrared radiation from 3 to 10 µm is a very promising way for spectroscopic study of gaseous, liquid, or solid species or intermixtures. We report a fast broadband tunable IR-light source based on the combination of a quantum-cascade-laser and a micro-opto-electro-mechanical systems (MOEMS) with integrated diffractive grating. This concept unites the advantages of broadband sources with the advantages of coherent laser sources in a miniaturized setup. The diffraction grating is processed inline within the MOEMS production process by non-isotropic etching. Grove depth and thus maximum spectral diffraction efficiency is determined by lithographic mask and the etch-parameters. The scanning MOEMS-grating is driven electrostatically and oscillates with high repeatability at resonance frequency of 1 kHz and up to 10° deflection, which allows scanning the entire spectral range of the QCL-chip within 500 µs. This opens the way for real-time spectroscopy in the MID-IR range. We present applications in non-contact detection of hazardous species e.g. explosives and inline-detection oil contamination in water.
Birger Seifert
Pontificia Universidad Católica de Chile, Chile
Title: Unambiguous ultrashort pulse reconstruction from double spectrograms alone
Biography:
Birger Seifert is an expert in the field of ultrashort light pulse characterization and his Doctor thesis was focused on this topic. He has in depth knowledge of the state of the art optical methods for the characterization of ultrashort light pulses, and the precluding background to the present status. In 2006 he invented and patented the dual spectrogram method known as very advanced method for phase and intensity retrieval of e-fields (VAMPIRE). He also works in quantum optics generating squeezed light, exploring quantum-well structures and quantum dots and measuring the coherent secondary emission from excitons bringing new insight about the decoherence processes in semiconductors.
Abstract:
In this work a fully analytic ultrashort pulse reconstruction technique which can be used to characterize two different ultrashort pulses of different center wavelengths and spectral ranges is presented. The proposed non-interferometric spectrographic reconstruction method is not based on an iterative Fourier transform algorithm or an ill-posed inversion problem in general, and the experimental setup is a simplified version of a dual spectrogram method known as ‘very advanced method for phase and intensity retrieval of e-fields’ (VAMPIRE). By using a dispersive element within the VAMPIRE setup, as shown in figure 1, which exhibits close to quadratic dispersion over a wide spectral range a mathematical approach can be borrowed from tomographic pulse reconstruction methods and used to reconstruct pulses from spectrographic information. The particular dispersive element used is BaF2 which exhibits a near quadratic spectral dispersion over the spectral range 200 to 1200 nm. Where the spectral dispersion is near quadratic the conditions for a tomographic approach to reconstruction are satisfied. Both spectrograms are thus related mathematically by the well-defined dispersive properties of BaF2. Wigner-Ville function projections are used to extract spectral phase information present in both spectrograms. Thus, the uniqueness conditions of the reconstructions can be discussed and justified mathematically. This is an important feature of the here proposed method, compared to previous versions of VAMPIRE. From our results we can demonstrate an analytic, fast, and simplified spectrographic pulse reconstruction method.
Gohar Tsakanova
Institute of Molecular Biology NAS RA, Armenia
Title: The study of natural anti-aging compounds using two-photon microscopy technique
Biography:
Gohar Tsakanova, PhD is a Senior Researcher and Deputy Director in the Institute of Molecular Biology NAS RA (National Academy of Sciences of Republic of Armenia). She has an extensive international experience having been invited to be trained or conduct research at prominent academic institutions in Germany, Denmark, Switzerland, Belgium and Hungary. She has also teaching experience having lectures on Proteomics and Protein Engineering Master Courses at the International Scientific-Educational Center NAS RA and Russian-Armenian University from 2013. Her primary work is related with the molecular and cellular pathomechanisms of ischemic stroke, aging and cancer, with the focus on immunology, genomics, neurobiology and two-photon imaging.
Abstract:
Statement of the Problem: The non-controlled accumulation of oxidative damage is one of the crucial mechanisms of the aging process. Antioxidant defense is the main mechanism controlling the over generation of reactive oxygen species (ROS) thereby protecting the organism against oxidative damage. Nowadays, finding of natural compounds protecting different cell types against oxidative stress is of most importance. From this perspective, Helix pomatia snails can be considered as such protecting compounds due to their well-developed strategy of defence against oxidative injury.
Methodology & Theoretical Orientation: In total, 30 healthy volunteers (25-35 years young age group, male/female, 5/5; 45-55 years middle-aged group, male/female: 5/5; 65> years older-aged group, male/female: 5/5) were involved in this study. The albumen gland extract was isolated from 40 adult specimens of snails. After the generation of an in vitro model of oxidative stress the intracellular ROS were monitored in human red blood cells (RBCs) with and without albumen gland extract by two-photon laser scanning fluorescence microscopy using a ROS-sensitive, membrane-permeable fluorescent dye, 5(6)-carboxy-2',7'-dichlorofluorescein diacetate (carboxy-DCFDA).
Findings: According to the results obtained, Helix pomatia snails albumen gland extract significantly (P<0.05) reduces the oxidative stress not only in intact RBCs from the older-aged group, but also in RBCs from this group exposed to additional in vitro oxidative stress.
Conclusion & Significance: In conclusion, the snail’s albumen gland protein extract effectively prevents the generation of intracellular ROS thereby demonstrating powerful antioxidant properties, and possesses a protecting effect against aging-generated ROS in human RBCs. And finally, the snail’s albumen gland protein extract can be considered as harmless and effective natural antioxidative means in prevention of the aging-related pathological processes associated with OS.
Nikolay A Nosyrev
JSC Shipbuilding & Shiprepair Technology Center, Russia
Title: Arc augmented laser technology for complex hull structures production in various spatial positions
Time : 15:50-16:15
Biography:
Abstract:
The shipbuilding industry requires high-performance production technologies for the heavy gauges. One of the key tasks in advancing of hull production technology is a minimization of welding deformations and simultaneous provision of high production performance. Anarc augmented laser-arc welding technology which provides higher productivity, improvement of production effectiveness and reliable quality of welded joints is the most promising technology for this task. Results of welding process simulation and experimental researches fulfilled on the preproduction models of technological complexes developed by JSC SSTC (based on fiber lasers up to 25 kW power) are presented. The welding technological processes for shipbuilding steels 7-40 mm thickness in various spatial positions were designed (including approved by qualification agency Russian Maritime Register of Shipping (RMRS)). Implementation of arc augmented laser technology for complex hull structures production allows to achieve a new level of productivity and manufacturing of structures in modern shipbuilding.
Manuel I Marqués
IFIMAC - Universidad Autonoma de Madrid, Spain
Title: Electromagnetic drag and diffusion control
Biography:
Manuel I Marqués obtained his BA in Physics at Universidad Complutense de Madrid in 1995 and was awarded with an extraordinary PhD prize in Physics at Universidad Autónoma de Madrid in 2000 under the supervision of Prof. Julio Gonzalo. He is a Fulbright fellow at Boston University from 2001 to 2003 where he performed a Postdoctoral research in the group of Prof. Gene Stanley. In 2003 he was awarded with a Ramón y Cajal appointment at the Universidad Autónoma de Madrid. He is now an Associate Professor in the Material Physics Department and Member of the Institute of Condensed Matter Physics (IFIMAC). His research interests are mainly focused on phase transitions and light matter interactions. He has coauthored more than 80 scientific articles with more than 1100 citations.
Abstract:
Fluctuating isotropic electromagnetic fields are obtained by considering a group of plane waves with wave vectors, polarizations and phases randomly distributed and fluctuating on time. Due to the isotropic character of this electromagnetic field, the optical force induced on a nanoparticle is, in average, equal to zero. However, the dynamics of electric dipoles on these kind of systems are far from being trivial. Due to the nonzero value of the optical force fluctuations, super diffusive, diffusive and accelerated regimens are induced on a single dipole. In this work, the expressions for the random force fluctuations, the optical drag force, the equilibrium kinetic energy and mean square displacement are derived. The conditions to be fulfilled by the polarizability of the dipole in order to obtain a positive, a null, and a negative drag coefficient are analytically determined and checked against numerical simulations for the dynamics of a silver nanoparticle.
Guy Stéphan
Université Lyon, France
Title: Polarization control in optical waveguide via chirality
Biography:
Guy Stéphan is a Professor at the ILM in the Materials and Photonic Nanostructures team. He received his PhD in Physics from the University of Lyon in 1995. His area of expertise is light matter interaction, rare earth spectroscopy, planar waveguides and chiral spectroscopies. He manages the chirality thematics of the MNP team. To date, he has co-authored 55 publications, his research in the field of chiroptic guides led to the first publication showing the control of polarization via chirality in waveguides.
Abstract:
Transverse polarizations in planar optical waveguides are reduced to the two well-known linear TE and TM polarizations. As a consequence, any set-up requiring other polarizations, especially the circular polarization (chiral sensing, 3D-display, quantum optics...), cannot take the full advantage of integrated optics. Here we report on the first achievement of planar optical chirowaveguides capable of propagating any expected state of polarization. While keeping the planar geometry of the device, the planar symmetry is overcome by using a chiral material for the guiding core. We developed chiral organically modified silica (OrMoSil) based chirowaveguides using the simple dip coating technique. Their refractive indexes (RI) can be modulated by triethoxysilane doping. The polarization of the two fundamental guided modes is measured on 3 cm long waveguides. We demonstrated that the polarization can be varied from linear to nearly circular depending on the RI contrast and the core thickness. These unprecedented achievements allow additional possibilities to planar waveguides that can give rise to novel highly integrated photonic devices based on circularly polarized light propagation.
Biography:
Tina Matzat is an independent filmmaker and founder of Qbit Films – a production company based in Berlin. While studying information sciences in Potsdam, she was confronted with the limitations of artificial intelligence and the implications of model and system theory – topics that found their way back into her writing while working on the current project '3025' – a metaphysical sci-fi script set in a futuristic world based on the principles of quantum physics and beyond.
Abstract:
The main problem the protagonists in the science fiction film '3025' are facing is the same that A.I. researchers are facing which is also the main problem of system theory: Would it be possible to create / exist outside the box? So the idea of free will and the power of consciousness are the main themes. After all, in a system where consciousness creates matter, everything that is thinkable is possible and the system (the human) should be able to emancipate from its original source. As a basis for this futuristic world the film offers various theoretical explanations about the beginning of our universe, humanity's origin, evolution and purpose, the nature and fabric of our reality, black and white holes, quantum entanglement, decoherence and indeterminism – inspired by (meta)physics and quantum sciences.