Day 2 :
- Optoelectronic Materials and Devices| Optical system| Optical networking | Nanophotonics
Location: July 29, 2016- Embassy I+II
Abdullah J Zakariya
Ministry of Interior Kuwait, Kuwait
E U Rafailov
Aston University, UK
Tsinghua University, China
Title: The quantum dot spectrometer-Exploiting the limitless number of colors of QDs
Time : 09:00-09:20
Jie Bao is an Associate Professor in the Electronic Engineering Department of Tsinghua University. Before joining Tsinghua, he graduated with a PhD degree from Brown University and carried out his Post-doc research at MIT. He is a member of the National 1000 Plan Professorship Program in China, and was awarded with ‘10 Emerging Star Scientists in China’ in 2015.
Speaking of quantum dots, the first thing that comes to mind is probably their most distinctive and characteristic property-that their band gaps, thus colors, can be continuously and finely tuned over a wide range. This property gives rise to a large pool of countless number of materials, which all share very similar natures and properties. In this speech, I will talk about how such a unique property is being exploited by the invention of the quantum dot spectrometer, and how we envision a ubiquitous sensing toolbox emerging out from a nano dot.
Abdullah J Zakariya
Ministry of Interior Kuwait, Kuwait
Title: Monolithically integrated tunable QW laser
Time : 09:20-09:40
Abdullah J Zakariya has completed his PhD from University of Central Florida. He worked as a Wireless Communications Engineer for 15 years and currently holds the position of the Wireless Networks Director at the Ministry of Interior – Kuwait where he takes up a variety of projects involving wireless public safety networks, telecommunications jammers and MPLS optical fiber networks. He also has several publications in the optics field specifically in tunable lasers and LEDs; moreover, he has several publications in the biomedical optics field focusing on point of care testing and lab-on-a-chip devices.
A monolithically integrated broadly tunable MQW laser that utilizes a combined impurity-free vacancy disordering (IFVD) of quantum wells and optical beam steering techniques is proposed, fabricated and investigated experimentally. The device consists of a beam-steering section and an optical amplifier section fabricated on a GaAs/AlGaAs quantum well (QW) p-i-n heterostructure. The beam steering section forms a reconfigurable optical waveguide that can be moved laterally by applying separately controlled electrical currents to two parallel contact stripes. The active core of the gain section is divided in into selectively intermixed regions. The selective intermixing of the QW in the gain section results in neighboring regions with different optical bandgaps. The wavelength tuning is accomplished by steering the amplified optical beam through the selected region where it experiences a peak in the gain spectrum determined by the degree of intermixing of the QW. The laser wavelength tunes to the peak in the gain spectrum of that region. The IFVD technique relies on silica (SiO2) capped rapid thermal annealing and it has been found that the degree of intermixing of the QW with the barrier material is dependent on the thickness of the SiO2 film. Optical characterizations of the intermixed regions have shown a blue shift of peak of the electroluminescence emission of 5 nm, 16 nm and 33 nm for the uncapped, 100 nm and 200 nm respectively when compared to the as grown sample. The integrated laser exhibited a wavelength tuning range of 17 nm (799 nm to 816 nm).
Shenzhen University, China
Title: Spectrum-polarization encoding for broadband laser pulses basing on rotatory dispersion and its possible applications
Time : 09:40-10:00
Shixiang Xu has completed his PhD in 1998 from Shanghai Institute of Optics and Fine Mechanics, China. His current position is a Professor in Shenzhen University. His research interests include ultrashort pulse laser, ultrafast imaging and pulsed terahertz optics. Till now, he has published more than 60 papers in peer-reviewed journals and 15 patents. He also serves as a member of Laser Professional Committee of Chinese Optical Society. Recently, he has been elected to the Council of Guangdong Optical Society of China.
As we know, Chirped Pulse Amplification (CPA), a kind of time-spectrum encoding, has scaled the femto-second pulse to several petawatts. Here we report a novel technology; we call it spectrum-polarization encoding (SPE) for broadband pulse. SPE can originate from the optical rotatory dispersion of some optical active materials, e.g. quartz crystal, and can be compensated by inducing equal value of the rotatory dispersion but with opposite sign. By using Ti:S as a polarization-dependent gain, our calculations show proper SPE allows an amplifier to boost an 800 nm pulse up to mJ level with a bandwidth to support few-cycle pulse duration. Further, M. Kalashnikov claimed that SPE might open a way to produce PW few-cycle laser pulses in a CPA system. We also find SPE may be able to tune output spectrum of a tunable laser with a polarization-dependent gain medium, to shape the ultrashort pulses by inducing polarization-dependent loss, to manipulate the nonlinear frequency conversion by encoding the refractive indices via the frequent components of the pumping pulses in a birefringent crystal and so on.
Boian Andonov Hristov
Bulgarian Academy of Sciences, Bulgaria
Title: Exact analytical aberration theory of centered optical systems containing conic surfaces
Time : 10:00-10:20
Boian Andonov Hristov is a Senior Research Fellow (Prof.) in Optics. His PhD is from Saint Petersburg State University of Information Technology, Russia. He had been member of the Faculty of the Military Institute of Optics and Laser Technology in Sofia, Bulgaria and member at the Institute of Optical Materials and Technology at the Bulgarian Academy of Sciences. He has published more than 60 papers in professional journals and proceedings from international conferences in Bulgarian, Russian and English. He is member of SPIE and has H-index 5.
The paper presents the development of exact analytical aberration theory (EAAT) of centered optical systems for conic surfaces such as oblate spheroid, sphere, ellipsoid, paraboloid, and hyperboloid. Provided are theorems of conjugate points and surfaces. We mean paraxial achromatic points, anastigmatic, plan sagittal, plan tangential, flat-field, orthoscopic, and surfaces with corrected tangential or sagittal coma which exist in the object and image space of every centered optical system, containing conical surfaces. To calculate the coordinates of the above mentioned points and surfaces in the object and image spaces of the optical systems we present accurate formulae. EAAT is able to correct one or several aberrations by calculating the constructive parameters such as radii and axial thicknesses. Furthermore, it is also possible for optical components or systems to be synthesized with precise corrected image aberrations and with given in advance object aberrations (to compensate the aberrations of preceding systems). Both the accuracy of the aberration correction and the calculation of the parameters (excluding tangential and sagittal coma) is about 10-10 mm. We present a variety of examples to illustrate the applied strength of EAAT. EAAT may be successfully used in all spheres of photonics and may accelerate drastically the research cycle in photonics technology.
University of Science and Technology of China, China
Title: Quantum algorithms for factorization problem
Time : 10:20-10:40
Xinhua Peng received her PhD degree in Atomic and Molecular Physics from Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, in July 2003. After that, she arrived at the University of Dortmund, Germany, as an Alexander von Humboldt Fellow. Since 2008, she is Professor at University of Science and Technology of China. She was awarded National Science Fund for Distinguished Young Scholars. She has published more than 50 papers in reputed journals.
Factorization of large numbers is a computationally hard problem on a classical computer: the computational resources required to accomplish this task increase exponentially with the size of the problem. Quantum computer could be much faster than classical ones in solving the factoring problem. Shor's algorithm is the most famous one. There are other methods for this problem, for example, adiabatic quantum algorithm and the Gauss-sum algorithm using properties of Gauss sums. Based on the idea of adiabatic quantum computation, we implemented the factorization of 143 by adiabatic quantum computation using nuclear magnetic resonance techniques, which is, we believe, the largest number factored in quantum-computation realization. On the other hand, relied on the properties of Gauss sums, we propose an efficient and exact quantum algorithm for finding the square-free part of a large integer - a problem for which no efficient classical algorithm exists. This algorithm overcomes the challenge that how to reduce the computational complexity by combining quantum entanglement with Gauss sums, and the introduced new concepts and methods may be applicable to a wider class of problems.
DO Tan Si
HoChiMinh-city Physical Association, Vietnam
Title: Fourier transforms of geometric forms and interference patterns, deflection of light by the sun
Time : 10:40-11:00
DO Tan Si has completed his PhD in 1971 and is a Researcher at the Université Libre de Bruxelles and the Universíté de l’Etat à Mons (Belgium); Lecturer at the HoChiMinh-city Natural Sciences University (Vietnam) and is now retired. He researches on mathematics and concentrates on the differential transforms including almost the Fourier transform; on differential calculus for resolving differential equations, linking special functions with monomials, modernizing the Laplace transform and, in physics, is author of the paper “On amplitude of Fraunhofer diffraction of waves by 3D objects”.
Consider an object defined by a function equal to unity for a point inside a domain D and to zero for a point outside. Consider the diffraction of a plane wave by this object. The diffracted wave may be described by the function . The probability for finding a plane wave in the diffracted wave is proportional to the square of the integral over the whole space of , i.e., the Fourier transform of calculated for . The problem of calculating the amplitude of diffraction and interference patterns is thus reduced to that of calculating the Fourier transforms of geometric forms. The aim of this work is to popularize the method for performing these calculations which is based on the properties of the Dirac delta and the Heaviside functions, the reciprocal vectors as explained in the previous work “On amplitude of Fraunhofer diffraction of waves by 3D objects”. Results of calculations for the cases of a point, an array of points, an array of stripes, discs, array of spheres and ellipsoids, cones, cylinders, intersections of them are given, completing the results obtained in the previous work. An attempt to calculate the angles of deflection of light by the form of the sun is also done and perhaps shows that the deflection given by General relativity is the sum of those by the form and the mass of the sun?
Centre for Life Nano Science, Italy
Title: Brillouin microscopy for sub-cellular 3D mechanical imaging
Time : 11:15-11:35
Giuseppe Antonacci has completed his PhD from Imperial College London. He is a Research Associate at the Italian Institute of Technology and is an Editor for the De Gruyter Physics.
Brillouin spectroscopy has shown great potential to become a reliable diagnostic tool due to its capability of measuring viscoelastic properties of materials in a non-contact manner. The recent development of high-sensitivity CCD cameras and Virtually Imaged Phase Array (VIPA) etalons has dramatically reduced data acquisition time to ~0.1 sec per spectrum. This has brought Brillouin spectroscopy from a point sampling technique to a new imaging modality. We describe the characterization of a confocal Brillouin microscope designed to measure mechanical properties of biological tissues. The frequency broadening of the Brillouin spectrum due to high illumination and collection apertures has been investigated in order to determine the optimal geometry that maximizes both the spectral and the optical resolution. A high extinction ratio was achieved in a Michelson interferometer to suppress strong specular reflections. Sub-micron resolution Brillouin images of single cells and arterial wall tissues have been acquired, in particular when atherosclerotic plaques were formed. These results might encourage the application of Brillouin microscopy as a tool of choice in clinical practice.
Northeastern University, China
Title: Router and routing designs for 3D torus optical network on chip
Time : 11:35-11:55
Weigang Hou has completed his PhD from Northeastern University (China) School of Computer Science and Engineering. He was the Research Associate from City University of Hong Kong Department of Computer Science. He is currently the Associate Professor of Northeastern University (China). His research topics including elastic optical network, optical data center network, optical network on chip, space information network and software-defined optical network. He has published more than 50 papers in conferences and journals including IEEE/OSA JLT, IEEE/OSA JOCN, IEEE Network, IEEE Globecom, IEEE ICC, etc.
With the rapid development of electronic products, the high-speed computing applications pose greater demands of the on-chip performance, which cannot be coped with the Network on Chip (NoC) because of its inherent limited bandwidth and low communication efficiency. Recently, the Optical NoC (ONoC) has emerged as a promising solution. Furthermore, 3-Dimensional (3D) ONoC was proposed to reduce the communication conflict among the significantly increasing number of Intellectual Property (IP) cores on the ONoC. However, current optical routers with 3D ONoC topology have redundant crossbars, and the routing algorithm lacks agility and relies on the deterministic strategies without the awareness of the network status. More importantly, the previous routing algorithms were designed with the objective to either minimize the power consumption or transmission delay. Different from large-scale optical networks, the OnoC pays more attention to its transmission reliability, since the wavelength drift will occur if the heat dispersion varies, which deteriorates Signal-to-Noise Ratio (SNR). In this paper, we propose new bidirectional and vertical optical routers for 3D Torus topology, in order to save chip resources. Then, we model the structure of these routers and propose corresponding routing algorithms. The microcosmic packet forwarding algorithm is utilized for each kind of router, meanwhile, the power loss and crosstalk on the optical signal along the light path are analyzed in our adaptive macroscopic routing, with the consideration of thermal-sensitive wavelength drift. Our mathematical analysis and simulation results demonstrate the effectiveness of our methods. Especially, the effectiveness of our routing algorithm is demonstrated via bound analysis.
E U Rafailov
Aston University, UK
Title: New generation of a single-chip LEDs with superior colour rendering emission
Time : 11:55-12:15
E U Rafailov received the PhD degree from the Ioffe Institute. In 2005, he established new group and in 2014, he and his Optoelectronics and Biomedical Photonics Group moved to Aston University. He has authored and co-authored over 400 articles in refereed journals and conference proceedings. He has coordinated a €14.7M FP7 FAST-DOT project – development of new ultrafast lasers for Biophotonics applications. Currently, he coordinated the €11.8M NEWLED project which aims to develop a new generation of white LEDs. He also leads a few others projects funded by FP7 EU and EPSRC (UK). His current research interests include high-power CW, ultrashort-pulse lasers; generation of UV/visible/IR/MIR and THz radiation, nano-structures; nonlinear and integrated optics; Biophotonics.
Development of LED-based solid state lighting has led to understanding that various lighting applications provide very different requirements to the quality and characteristics of white light. The mainstream applications, like outdoor (street) and indoor lightings are primarily aimed at saving electricity consumption and, therefore, need maximum efficacy and minimum cost of white-light source. Warm-white emission with superior CRI is demonstrated using a di-chromatic monolithic InGaN multiple quantum well LED and two phosphors. The LED emitting simultaneously blue (440 nm) and cyan (480 nm) photons pumps the vertically stacked red (~ 620 nm) and green (~540 nm) phosphor. An excellent average colour rendering index, CRI (Ra) of 98.4 with CCT of 3400 K is achieved. With appropriate heat sink assembly and industry standard packaging to improve extraction efficiency we estimate these devices can achieve Luminous Efficacy and Wall-plug Efficiency (WPE) of more than 160 lm/W and 55% respectively.
Sanjeev Kumar Raghuvanshi
Indian School of Mines, India
Title: Photonic microwave arbitrary waveform generation with adjustable chirp parameter based on remote sensing applications
Time : 12:15-12:35
Sanjeev Kumar Raghuwanshi is working as an Assistant Professor in the Department of Electronics Engineering at Indian School of Mines, Dhanbad since March 2010. He has completed Post-doctorate at Instrumentation and Sensor Division, School of Engineering and Mathematical Sciences, Northampton Square, City University, London. He obtained PhD degree in the field of Optics from the Department of Electrical Communication Engineering of Indian Institute of Science, Bangalore, India. He has published more than 200 papers in reputed journals and conferences and serving as an Editorial Board Member of repute.
The objective of this paper deals with various methodologies for generation of photonics microwave waveform using adjustable chirp parameter. In this paper, the research efforts have been focused on the investigation of innovative optical techniques to generating and processing high frequency and large bandwidth (extended from E band to K band with adjustable chirp factor) microwave arbitrary waveforms using advanced Fibre Bragg Grating (FBGs) with single and cascaded Mach Zehnder Modulators (MZM). Photonic generation of microwave arbitrary waveforms based on coherent optical pulse shaping using advanced FBGs is proposed to be studied experimentally and theoretically. Two different methods for photonic microwave arbitrary waveform generation (with single and cascaded MZM configuration) are proposed to be investigated. Advanced FBGs have been employed in the systems as an optical spectral filters and dispersive elements. Different types of FBGs are proposed to be investigated, which have a very important role in the proposed microwave arbitrary waveform generation and processing systems, with the advantages of small size, low loss, low cost, good stability, and high compatibility with other well developed fiber optic devices. Besides it dispersion is one of the major limiting factors for the microwave signal generation in microwave photonics. Theoretically, influence of higher order dispersion parameters on microwave signal generation has been investigated under this talk for the case of single and cascaded MZM configuration. The FBGs have to be incorporated into the proposed systems to achieve microwave arbitrary waveform generation and processing.
- Optical Sensor Technologies and Types | Medical Laser Technology | Optometry Practice
Location: July 29, 2016- Embassy I+II
German F de la Fuente
ICMA CSIC-University of Zaragoza, Spain
University of Guayaquil, Ecuador
University of Guayaquil, Ecuador
Title: Importance of early diagnosis Retina
Time : 12:35-12:55
Daniel Valverde is presently working as a Faculty of Medical Sciences at University of Guayaquil. He is a specialist in retina medicinal, ocular nutrition, low vision, pediatric vision, public health and many community development projects in public health. He is a fellow member in Public Health of Inter-American University of Puerto Rico. He has completed his Continuing Education from The New England College of Optometry, Boston, USA. He is a member of the AOA American Optometric Association, International Council of Ophthalmology, Ophthalmology Education Committee, Ocular Nutrition Society USA and OSH President. He is a Lecturer in North America, Central America, South America, Europe and Asia.
One area that has been somewhat neglected in clinical practice of optometry is undoubtedly the retina. This being the main axis where vision develops, certainly you have to consider this fact. In our offices, there is no need of any sophisticated equipments, we can have a direct ophthalmoscopy to determine what we see and how we see. This provides early diagnosis for allowing us to provide our patients the opportunity to prevent permanent blindness. Management of preventive actions with antioxidants and ocular nutrition certainly gives us another stage start in the fight against prevention of blindness. Recall that in the levels of patient care, designed by the World Council of Optometry, approved in Dallas Texas in 2006, is set to the third level of care the patient's ocular diagnosis as a tool of action in clinical practice. We know that today Europe has experienced great development in the training of optometry, but we also know that not all countries of the continent are experiencing this academic development, which drives us to achieve standardization in clinical practice, and the early diagnosis of problems in retina makes a big difference in what we see? How we see? What we are shown? Because the retina is the key to success, finding a healthy retina and differentiating it from some problems for referral to retinologist gives the patient a great alternative.
German F de la Fuente
ICMA CSIC-University of Zaragoza, Spain
Title: The laser furnace: Enabling continuous processing of ceramics and glass under extreme conditions
Time : 12:55-13:15
Germán F de la Fuente is a Research Professor at the Spanish National Research Council (CSIC) working at the Aragón Institute for Materials Science (ICMA). He started the Laser Applications Laboratory at ICMA about 25 years ago, a reference in Laser Ablation and Melting and has developed large area laser surface coating and modification methods for ceramics, glasses and metals. He is co-inventor of 10 patents, coauthor of 140+ scientific papers and has coordinated a large number of projects based on the use of laser technology developed in his research group.
Laser processing of ceramics and glass has been proposedas a method to enable a multitude of surface functionalities and unforeseen relevant applications, although laser-induced thermal shock has hindered full use of lasers within these industrial sectors. Most of the former materials suffer cracking and eventually, catastrophic failure as a consequence of accumulated thermo-mechanical stress. In order to avoid this problem, a patented device has been developed which combines continuous laser scanning with uniform movement of the samples across a roller kiln kept under a convenient temperature profile. This unprecedented methodology enables treatment of any surface at extreme temperatures, while the sample’s volume is kept at reasonably low temperatures. For example, BaZrO3 coatings melting near 3000ºC have been processed over Al2O3 substrates at temperatures around 2100ºC or over porcelain tiles at 1140ºC, insuring very robust coatings integrated at the atomic scale into the substrate. This talk will present the Laser Furnace models developed so far and will review the most relevant results obtained to date in glass and ceramics.
Nezar R Damati
Eyezone Institute of Opticianry and Private Training, Kuwait
Title: Scleral contact lens for KC management
Time : 13:55-14:15
Nezar Damati completed MBA degree. He is a Doctor of Optometry, Professional Academic Educator, highly motivated Optometrist, CL Practitioner and Consultant in fitting for the most prestigious clinics and optical chains. He has extensive experience in ECP, an exposure in CL education, and training programs on leadership in CL fitting. He is a Certified International Professional Trainer and Executive Director at Eyezone Institute of Opticianry and Private Training, Kuwait.
Learning Objectives: Upon completion of this program, the participant should be able to understand the new generation of large RGP design lenses; learn more about fitting techniques for scleral lenses and understand the indication and patient candidate of scleral lenses. Course Description: Keratoconus, often referred to as “KC,” is a slowly progressive, non-inflammatory eye disease that causes the cornea to thin and assumes an irregular conical shape appearance. The cornea refracts the majority of light that enters the eye so abnormalities or injuries to the cornea can significantly affect patient vision and impair the ability to perform simple tasks and duties like driving (especially night driving), daily activities, watching TV, or reading a book. This course describes keratoconus and treatment with RGP scleral contact lenses. Conclusion: Fitting the keratoconus patient is challenging. Scleral lenses represent one of the most important tools available to fitters today. Their use should continue to increase because they offer excellent vision, good initial comfort, and they eliminate concentration related problems that can occur with smaller diameter lenses.
Nanjing University of Information Science and Technology, China
Title: Aerosol profiling by Raman Lidar in Nanjing, China
Time : 14:15-14:35
Nianwen Cao has completed his PhD from Anhui Institute of Optic & Fine Mechanics, Academic of Science of China. He is a Professor, engaged in Atmospheric Remote Sensing by Lidar, at Nanjing University of Information Science & Technology. He has published more than 40 papers in reputed journals.
The aerosol measurements by using Raman-Mie-Rayleigh Lidar in Nanjing, China, were presented in this paper. The Lidar system consisted of transmission at 532 nm and receiver with 3 different channels. The aerosol Lidar signals generated from backscatter lights were obtained simultaneously from Raman (607 nm)-Mie (532 nm)-Rayleigh (532 nm) Channels. Aerosols at low/high altitude were measured by Mie/Rayleigh Channel at daytime, and measured by Raman Channel at night time. The start of data collection of Rayleigh & Raman Channel was controlled by the gate by setting different time delay. New aerosol extinction coefficient calculation methods by using Mie/Rayleigh Channel data were reported. According to the structure of Range corrected signal from Mie/Rayleigh Channel, the accurate extinction coefficient at the range of homogeneous aerosol layer was obtained, then, to be used as reference value to calculate the aerosol extinction coefficient profiles at whole range. The accurate aerosol extinction coefficient profile was obtained by comparison of different aerosol extinction coefficient profiles by slightly changing the boundary values. The aerosol optic properties were also calculated from the signals from Raman Channel by using Raman theory after Lidar data treatment by using multi-average calculation or small wave analysis. The aerosol extinction coefficient profiles obtained from Mie/Rayleigh Scatter were compared with from Raman Scatter. The aerosol extinction coefficients about 10-4 ~ 10-5 were calculated from Mie/Rayleigh Channels coincided with Raman Channel. The boundary aerosol optic properties were obtained by Mie/Raman channels, and aerosol optic properties at higher altitude were measured by Rayleigh/Raman channels. Aerosol parameters at different altitudes were measured simultaneously from one measurement by Raman-Mie-Rayleigh Lidar/Multi-function Lidar system.
Victor V Apollonov
Prokhorov General Physics Institute, Russia
Title: New applications for high repetition rate high energy P-P lasers
Time : 14:35-14:55
Victor V Apollonov is the leading specialist in the area of basic principles of creation and development of high energy laser systems and high energy laser radiation interaction with matter. He has made an outstanding input into creation and development of new branches of science - physical and technical fundamentals of high average power laser optics and adaptive optics, investigation of physical processes in a high volume self-controlled volume discharges, creation of high power continuous wave, pulsed and high repetition rate pulse-periodic laser systems, high energy laser radiation interaction with matter, and high energy laser application. He is the author of more than 1300 publications: 16 books, 368 presentations and 147 patents, 750 articles, (Research Gate). He is a full member of Russian Academy of Natural Science and Academy of Engineering Sciences, member of the Presidium RANS. He is the laureate of State Prize of USSR (1982) and of Russia (2002).
At present, we consider as most energetic and promising for high repetition rate pulse – periodic (P-P) laser applications carbon dioxide laser, chemical laser and solid-state laser. In the future, high-power high-frequency P-P lasers will find applications in the field of ecology of space. Besides, they will be used to transmit power over long distances, to obtain high-power plasma radiation in the range of ten to hundreds of Angstroms, to realize arbitrary geometry of the breakdown in a three-dimensional space, to produce ultrasound, electromagnetic fields etc. A new class of rocket engines – a laser jet engine (LJE) – objectively belongs to the most promising rocket engines of the foreseeable future. The LJE is substantially more cost-effective than conventional chemical fuel engines. At the initial stage of the flight, the LJE employs atmospheric air as a working medium and in outer space use is made of a small space-borne gas supply or an easily sublimated substance. In this case, the specific costs of the cargo launching to outer space may be reduced down to 150–300 USD/kg. The LJE-based solution of a series of very interesting and important problems is predicted, in particular designing of a space interceptor that would destroy debris and other dangerous space objects, such as asteroids, meteors, etc.; launching of macro-objects with a very high acceleration that is orders of magnitude greater than it can be done by existing technology; realization of super-long orbital-scale conducting channels for addressing the global challenges of ecology and energy transfer; laser-plasma generator of multiply charged ions produces a large number of heavy ions in the regime of short P-P pulses, which is of interest for ion accelerators operating in the P-P regime and many other applications of high energy P-P lasers.
Hee Kyung Ahn
Korea Research Institute of Standard and Science, South Korea
Title: Cascaded multi-dithering technique for high power beam combination setup
Time : 14:55-15:15
Hee Kyung Ahn has completed his PhD from Korea Advanced Institute of Science and Technology (KAIST) and Post-doctoral studies from Korea Research Institute of Standard and Science (KRISS).
Coherent beam combination is a way to obtain high power by coherently adding lower power beam elements and has been highlighted as an alternative to scale up the power of high power and high beam quality lasers which has faced several problems such as thermal effect and nonlinear effects. For combining a large number of beam elements, It is inevitable to use active phase control, which is to lock phases of beam elements and obtain maximum output power. There are several methods in active phase control such as heterodyne detection, stochastic parallel gradient descent (SPGD) algorithm, multi-dithering technique, and single-dithering technique. Among those methods, locking of optical coherence by single detector electronic-frequency tagging (LOCSET) technique, as known as multi-dithering technique, locks the phases of beam elements by modulating the phases with different frequencies and demodulating the signal of the combined beam with those frequencies. It has showed excellent performance in terms of phase stability and the number of beam elements to be combined. However, the maximum number of beam elements to be combined is limited up to 100 to 200 when combining high-power amplified beam elements using LOCSET, since the number of modulating frequencies is limited 100 to 200 because of the constraint of the control bandwidth of phase locking system. Cascaded Multi-Dithering (CMD) technique has been proposed to solve this limitation, by modulating beam elements in series and combining them as a form of array. It was successfully demonstrated by combining sixteen beam elements in 2015. Nevertheless, CMD technique also has a limit to combine high-power amplified beam elements because of low damage threshold of phase modulators which dither high power beam elements after amplification. In this paper, a new setup of CMD technique for high power beam combination is presented. By simply changing the configuration of CMD technique, the problem of low damage threshold of phase modulators is easily solved, which enhances the capability of CMD technique as a powerful tool for combining a substantial number of high power beam elements.
Kharazmi University, Iran
Title: Investigation of distribution mechanism of noise fluxes between three oscillating modes of a free-running class –A laser
Time : 15:15-15:35
Jafar Jahanpanah received the BSc degree in Applied Physics from Amir Kabir University, Tehran, Iran, in 1989, and the MSc degree in Optics Communication and the PhD degree in Laser Theory from Essex University, UK, in 1992 and 1995, respectively. He began his PhD research with Prof. R. Loudon with a focus on the gain, stability, and injection-locking topics in a single-mode laser amplifier. His current research interests include laser noise and also the gain, stability, and mode-locking phenomena in the multi-mode lasers. He has published many articles in journals of PRA, OSA, applied physics, optics communications, and IOP.
In this paper, the noise aspects of a class-A laser from the single mode state with one cavity damping rate are extended to the more general case of three-mode state with the three equal cavity damping rates.The cavity Langevin force is thus divided into three parts , , and associated with the simultaneous oscillations of cavity left, central, and right modes, respectively. In this way, the phase and amplitude fluctuations of cavity electric field components are analytically calculated by solving the three-mode Maxwell-Bloch equations of motion in the presence of three fluctuating cavity Langevin forces.The correlation functions of three latter cavity Langevin forces are then used to calculate the noise fluxes that are simultaneously superimposed on the mean energy fluxes of oscillating modes in the form of stimulated emission radiation. The most advantage of our calculations is to determine the exact share of each oscillating mode in the total noise flux spectra of laser, spontaneous emission, and pumping of a three-mode class-A laser. The results indicate that the cavity Langevin force of each of three oscillating modes makes a direct contribution in producing the noise fluxes of other two oscillating modes. Our model is finally confirmed by demonstrating a balance relation between the input pumping noise flux and the output noise fluxes of laser and spontaneous emission of three oscillating modes.
Shandong University, China
Title: Research progress on metal ions doped lithium tantalate crystals and their applications in green laser
Time : 15:50-16:00
Kang Xueliang received his Bachelor's degree at Shandong University in China in 2012 and has been studied in Institute of Crystal Materials of Shandong University as a Post-graduate student since then. His research focused on the growth, structure and physical properties of lithium niobate crystal and lithium tantalate crystal. He has published several literatures in some important journals.
Lithium tantalate (LT) is one of the most promising nonlinear optical materials. However, the low optical quality and damage threshold limits its application in photics. Therefore, growth of MgO doped LT and stoichiometric LT has become a hot research topic. Nd, Mg co-doped LT possess improved laser properties and these metal ions would help eliminate anti-site defect in crystals which affect the physical properties largely. However, the doping homogeneity is still a key factor which determines the quality of the crystals. Therefore, we focused on the research of crystal growth, ions doping and physical properties of lithium tantalate for years. We obtained MgO doped SLT and Nd, Mg co-doped CLT crystals with high homogeneity and great optical properties. We studied the anti-site defects in crystal lattice and elimination method. With the Nd, Mg co-doped CLT crystal, a CW laser output power of 3.58 W was achieved. A green laser with multi-wavelength emission was demonstrated using intracavity frequency conversion (frequency doubling and frequency summing) in a Nd:Mg:LiTaO3 laser. MgO-doped periodically poled lithium niobate (MgO:PPLN) was used as a nonlinear crystal in this work. Moreover, a 62mW that could emit light at 546, 542 and 538 nm was obtained by end pumping with a 808-nm laser diode. The speckle contrast ratio for the three-wavelength laser was only 3.36%, a quarter of the value of the conventional 532-nm laser, which showed that a multiwavelength broadband laser is an effective way to reduce the speckle noise in a laser projection display.
Helmholtz Zentrum für Materialien und Energie Berlin, Germany
Title: Laser processing of solar cells on laser crystalized silicon
Time : 16:00-16:10
Tim Frijnts has finished his MSc in Applied Physics at Delft University of Technology in 2010, after which he went to work as Device Expert at the thin film silicon solar cell company Masdar PV GmbH in Germany. At the end of 2013, he started his PhD at HZB/PVcmB (part-time), as part of an ambitious plan of Masdar PV and HZB to commercialize liquid phase crystallized silicon. When one year later Masdar PV decided to shut down, he had the opportunity to continue at HZB to finish his PhD.
Low quality silicon was deposited on silicon oxynitride layers on glass. This was then crystallized over a liquid phase using a line-shaped, 808 nm, continuous wave, diode laser, in order to obtain crystalline silicon with grain size comparable to multicrystalline silicon wafers. A 1064 nm picosecond laser, applied through the glass, was used to make isolation scribes which define the cell area and also allow for the fabrication of a mini-module consisting of series connected cells. A 355 nm picosecond laser, in combination with a white resin layer, was used to structure the contacting layers of the backside contacted solar cell, thereby avoiding the use of expensive and cumbersome lithography processes. Finally, a 532 nm nanosecond laser was used to modify the metal-silicon contact in order to reduce the contact resistance, resulting in a new highest efficiency for this cell type of 12%.
Héctor Santos Barahona
Complutense University of Madrid, Spain
Title: Surface alloying of Al coatings on P92 steels by laser line scanning
Time : 16:10-16:20
Hector Santos finished his Master’s in Chemical Engineering in 2007 and has since been working at the Surface Engineering and Nano-structured Materials Research Group of the Complutense University of Madrid. He is currently starting 4th year of his PhD studies.
Conventional protective coatings for energetic applications (e.g. heat exchangers, certain turbine components) are highly exposed to severe degradation conditions. High steam pressure and temperature, typical of high performance operating regimes have a dramatic effect over the materials’ long-term lifespan. Within this context, further expansion of conventional materials performance is of utmost importance, especially when revamping of existing facilities is in sight. Herein, we present a recently developed laser line scanning method for surface alloying treatments, based on directional solidification of an intermetallic coating, particularly adapted for the Al/P92 steel system studied. Such conventional material system has been widely reported in the literature using different preparative approaches. Much less common has been the work on laser treatments, particularly on directional solidification. Such directionality is partially achieved by processing samples at traverse rates with values ranging between 30 and 300 mm/h. Undesirable effects associated to aluminium oxide formation are reduced by using a controlled atmosphere chamber during laser surface alloying. This advanced laser line scanning method offers the means to effectively control the microstructure, surface and adherence properties of Al/P92 protective coatings.
Khaled M Saoud
Virginia Commonwealth University in Qatar, Qatar
Title: Utilization of continuous low power visible laser in the 3D printing of strong and ultra- light weight cross-linked silica aerogel
Time : 16:10-16:20
Khaled M Saoud is Associate Professor of Physics at Virginia Commonwealth University in Qatar. He has completed his PhD in 2005 in Chemical Physics at the Chemistry and Physics departments, Virginia Commonwealth University. He held many industrial positions at major American companies such as Philip Morris USA, Intel Corporation, and Nova Measuring Instruments Inc. He has been working in the field of Nanotechnology since 1998. He published over 40 research papers in the field of Nanotechnology and holds two US patents.
3D printing of strong and lightweight materials is playing an increasingly significant role in many applications such as the 3D printing of designs and prototypes, architectural models, consumer products, electronics, and printing technologies. Various materials and methods have been explored for 3D printing such as laser sintered metals, photo-cross-linked polymers and extruded molten polymers. Recently, lasers, laser-assisted 3D printings are getting much attention over traditional methods of 3D printing due to their flexibility and efficiency. Current 3D involve the use of a high power and pulse lasers such as carbon dioxide laser or ultraviolet lasers (UV). In this paper, we present the synthesis of polymer cross-linked silica alcogels in a matter of seconds by illuminating a precursor solution of an alkoxide, a monomer and a visible-light photo-initiator using a 2 Watt laser beam (532 nm). The illumination initiates free-radical polymerization then the heat of polymerization triggers gelation instantly. We have successfully demonstrated a manual printing of 3D letters on diﬀerent substrates like laminated paper, a glass slide and a silicon wafer using masking techniques, and also the printing of a 50 mm thick line on a glass substrate through direct shining of a laser on the liquid mixture without any mask. Our results indicate that the instantaneous and simultaneous polymerization and gelation of silicon alkoxide precursor and polymer can lead to the fabrication of mechanically strong and ultra-lightweight silica aerogels which oﬀers a new direction for the 3D industry.
Naimi E K
National University of Science and Technology “MISIS”, Russia
Title: 4D-Photonic crystals
Time : 17:35-17:55
Naimi Е K received PhD from Moscow State University and Dc. Sc. thesis from Moscow Institute of Steel and Alloys in 1993. In 1994, she worked as a Professor in Department of Physics. Her fields of research interests are solid state ultra-acoustics. She has published more than 50 papers in reputed journals.
One of the modern optics directions is the investigation of the so-called photonic crystals (PCs), a new class of ordered optical materials characterized by two main features: the periodic spatial modulation of the refractive index with a period allowing light Bragg diffraction and the existence of band gaps associated with translational symmetry of the refractive index in the spectrum of intrinsic electromagnetic states. The idea of the PC development belongs to E. Yablonovich and S. John (1987). It consists in designing new artificial media whose properties would make it possible to affect photons similarly to the effect of the ordinary lattice on electrons. Similarly to Bloch waves of electrons in ordinary crystals, optical waves in the PC lattice can have states in which the wave vector k (phase velocity) direction and the Poynting vector (group velocity) direction are anti-parallel. In other words, PCs can have a negative refractive index. The phenomenon of negative light refraction was most thoroughly considered by V.G. Veselago (1967). From the general point of view, the PC is a super lattice, i.e., a structure in which an additional field with a period exceeding the period of the basic lattice by several orders of magnitude is artificially induced. For photons, such a field is induced by periodic changes in the refractive index of the medium in one, two, or three dimensions (1D-, 2D-, and 3D-photon structures). The formation of dynamic periodic changes in the PC structure makes it possible to one more dimension, i.e., the time. A crystal obtained in such a way can be considered as a four dimensional (4D) photonic structure where the time is the fourth dimension. Due to the mutual influence of spatial and temporal processes, optical properties of such structures are potentially more diverse than properties of three dimensional crystals. In the present work we consider the conditions of the formation of the dynamic PC based on an optically homogeneous and isotropic medium with space–time modulation of the refractive index, implemented by an ultrasonic wave whose length exceeds the light wavelength by many orders of magnitude. To solve the posed problem in general form, we use Fermat’s principle. It has been shown that the excitation of a standing ultrasonic wave in the medium creates a structure consisting of trajectories of separate light beams, which is a super lattice of the dynamic 4D-photonic crystal. The band gaps corresponding to negative light refraction have been revealed in beam trajectories. Possible fields of application of such structures have been discussed.
Mikhail A Bisyarin
St.Petersburg State University, Russia
Title: Analytical approaches to description of nonlinear processes in inhomogeneous optical waveguides
Time : 17:55-18:15
Mikhail A Bisyarin has received his Doctor of Science (Phys. & Math.) degree in 2010 and continues his studies at St. Petersburg State University. He is a Head Researcher at the Department of Radiophysics and carries out research on analytical methods in the theory of non-linear oscillations and waves. He has published about 50 papers in reputed journals and has co-authored (with I. A. Molotkov and S. A. Vakulenko) the monograph entitled “Nonlinear Localized Wave Processes” (in Russian).
Despite a wide outspread of applied programming packages, the development of analytical methods for description of the nonlinear regime of the short modulated pulse propagation in a graded-index dielectric waveguide with longitudinal inhomogeneity remains an urgent problem. These are the analytical approaches that enable to study the very structure of the propagation process, each its component separately and their interaction, as well as to clarify the effects of various physical factors into the travelling pulse parameters. The pulse under scrutiny appears to be a sinusoid of an optical frequency with an envelope covering from several units through several tens of oscillations (sub-picosecond pulses), with the phase modulation, e.g. chirp, being also allowed. Considered as a propagation medium, is a graded-index waveguide - a planar or cylindrical dielectric with the refractive-index profile providing the wave field localization within the waveguide cross-section. The refractive index is supposed to depend on the longitudinal coordinate, and a slight bending of the waveguide axis is also allowed. The asymptotic technique proceeds from the generalized nonlinear wave equation, uses a unique small parameter, and allows in a natural way to extract a linear component of the process. This linear task defines the mode structure of the pulse, i.e. the propagation constant and the field distribution within the graded-index waveguide cross-section. A more realistic sech-refractive-index profile (instead of quadratic) is involved into analysis, nevertheless explicit formulae are derived in this case. The nonlinear pulse dynamics is characterized by a generalized nonlinear Schroedinger equation, its coefficients depend on material and waveguide dispersion and are functions on the longitudinal coordinate. This is substantial in taking into account the longitudinal inhomogeneity in describing the nonlinear pulse dynamics.