5^th International Conference and Exhibition on Lasers, Optics & Photonics November 28-30, 2016 Atlanta, Georgia , USA

Biography:

Vladislav E Bougrov is the Director of School of Photonics and Head of Chair of Light Technologies and Optoelectronics at the ITMO University, St. Petersburg, Russia. He has obtained his Master’s degree in Optoelectronics from Department of Optoelectronics, PhD in 1999 and DSc in Physics in 2013 from Ioffe Institute, St. Petersburg, Russia. He is the author of more than 60 papers in reputed journals, inventor in more than 100 patent applications, including more than 30 granted patents and has extensive experience with dynamic management of growing international start-up companies. He is the founder of Optogan.

Abstract:

Ever-growing demand for high-speed internet, optical interconnects in data centers; development of cloud technologies set a trend for moving communication technologies from electronics to photonics. Volumes of information transmitted in the last ten years increased by 50 times, continuing to grow at the same rate. 10% of all electric energy in the world is consumed by Internet, this demand doubles every four years. Combinations of optical and wireless communication technologies resulted in development of a new area of photonics – microwave photonics (MWP). Using MWP systems in hybrid fiber-radio system becomes crucial for reliable operation of next-generation intelligent optical network. To become a viable alternative for electronic components, photonic components must be fabricated in integrated-circuit form. Integration makes them reliable, compact, cost- and energy- effective, convenient for signal and inter-connect matching. III-V compound semiconductor materials are very promising for photonics integrated circuits (PIC) due to their ability to integrate both active and passive devices along with potential of offering cost effective mass production. Currently, PICs are essentially operating in analog mode. As a result, they accumulate the errors while cascading a number of devices. This results in severe degradation of signal quality and requires regeneration of signals. Electronic high speed analog-to-digital converters (ADC) are facing a limited effective number of bits at frequencies of more than 1 GHz due to timing jitter of electronic sampling clocks and ambiguity bottlenecks. To overcome the aperture jitter, it is crucial to perform sampling in the optical domain using low-jitter optical pulse trains generated by a mode-locked laser. We report on different layouts of photonic ADCs based on III-V semiconductor components. We report on modeling and fabrication of integrated 10 GHz III-V semiconductor components, such as monolithic mode-locked lasers, PIN photo-detectors based on InGaAs/InAlGaAs heterostructures, operating at wavelengths of 1520-1580 nm.

Biography:

Maria Tchernycheva is an Engineer from Ecole Polytechnique (X98). She has received PhD in Physics from the Université Paris Sud, Orsay (France) in 2005. In the year 2005, she joined the Laboratory for Photonics and Nanostructures, CNRS, Marcoussis, France as a Post-doctoral Researcher. Her work was focused on the fabrication of III-V and III-N semiconductor nanowires by molecular beam epitaxy. In 2006, she joined CNRS at the Institut d’Electronique Fondamentale of University Paris-Sud in Orsay where she is currently leading the “NanoPhotoNit” Research Group focusing on the fabrication and testing of novel optoelectronic devices based on semiconductor nanowires. She has published more than 100 articles in international journals, which gathered more than 2000 citations (her Hirsh index is 32). She received the Madeleine Lecoq award from the French Academy of Sciences in 2006.

Abstract:

“Photonics multiannual strategic roadmap 2014-2020” mentions flexible electronics, flexible light sources, displays and solar cells as key emerging technologies with high expected growth of the market share. Indeed, flexible devices offer new functionalities inaccessible with conventional technologies (e.g., rollable screens, bendable or implantable light sources, energy harvesters integrated in clothing, etc.) It is noteworthy that in the above-mentioned roadmap the notion of a flexible device is inseparable from an organic device. Technologies based on organic semiconductors have indeed made a huge progress in the past 10 years; however, organic devices still suffer from a short lifetime and low efficacy as compared to their inorganic counterparts. Taking an example of light emitting diodes (LEDs), organic LEDs suffer from strong degradation in the blue spectral range and their luminance at high current is low. Blue LEDs based on nitride semiconductors reveal high brightness and efficiency, yet conventional thin films represent rigid structures, which make fabrication of flexible devices rather difficult. In this context, nanowires offer an elegant solution to the problem. Single nanowires and nanowire array LEDs based on InGaN/GaN core/shell heterostructures have been successfully demonstrated on rigid substrates, showing excellent performances in the blue spectral range, thanks to their high crystalline quality and non-polar active region. I will present our recent work on nitride nanowire-based light emitters and photodetectors. These nanomaterials have the potential to boost the device performance, improve energy efficiency, reduce the cost, and bring new functionalities. In particular, I will discuss our recent progress towards flexible nitride nanowire devices: we propose a method to combine high flexibility of polymer films with high quantum efficiency provided by nitride nanowires to achieve flexible inorganic LEDs and light sensors.

Biography:

Roberto Morandotti has received his MSc in 1993 from the University of Genoa (Italy) and his PhD in 1999 from the University of Glasgow (UK). Since 2008, he is a Full Professor at Institute national de la recherche scientifique (INRS-EMT). Since 2015, he has been working as an Adjunct Professor at the University of Electronic Science and Technology of China (Chengdu‏, China) and is a Visiting Professor at ITMO (St. Petersburg, Russia). He is an E W R Steacie Memorial Fellow, a Fellow of the Royal Society of Canada, APS, OSA, IoP and SPIE, as well as the General Co-chair of CLEO QELS 2016.

Abstract:

Optical quantum states are fundamental for several applications ranging from sensing and secure communications to quantum computation. The generation of such quantum states on a compact integrated platform will allow for customizable, low-cost, and large-scale implementations, enabling accessible advances for quantum technologies. With current advances in optical quantum information processing (e.g. the realization of the first commercial quantum cryptography systems and computers), it is foreseeable that such reliable, low-cost and scalable on-chip sources of single and entangled photons will represent a key enabling technology for quantum applications. Therefore, the realization of integrated quantum sources has attracted considerable attention from the scientific community. However, major difficulties arise when sources need to satisfy several requirements at the same time, i.e. a narrow spectral bandwidth, high-purity single-mode generation, high production rates, stable long-term operation, multiplexed broadband operation, and high-quality entanglement shared between photons. We show that integrated quantum frequency comb sources can address these important requirements. We demonstrate the generation of pure heralded single photons, cross-polarized photon pairs, as well as entangled two- and multi-photon photon states, distributed over many frequency modes and spanning the complete fiber-optical telecommunications band. Integrated quantum frequency combs therefore provide a scalable and versatile platform for quantum information processing. 

Biography:

Karim D Mynbaev has received his MSc in Optical-Electronic Systems from St. Petersburg Electro-technical University “LETI” in 1986, and his PhD and DSci degrees in Semiconductor Physics from Ioffe Institute in 1992 and 2007, respectively. His research interests mostly concern narrow-bandgap semiconductors and optoelectronic devices designed to operate in the mid-infrared (2-6 µm wavelength range) part of the spectrum, based on II-VI (Hg,Cd)Te and III-V (InAs(Sb,P)) systems. He is also involved in the studies of defect structure of wide-bandgap materials, such as SiC and GaN. He has authored and co-authored more than 100 papers in international peer-reviewed scientific journals and 2 book chapters. Currently, he heads the Laboratory of Photoelectrical Phenomena in Semiconductors at Ioffe Institute, and serves as a Professor at the Chair of Light Technologies and Optoelectronics at ITMO University.

Abstract:

According to conventional wisdom, in regards to optoelectronics, III-V semiconductor materials prevail over their II-VI counterparts due to stronger chemical bonds and more advanced fabrication technology of the former. Ever increasing demand in various types of optical sensors, especially these operating in the infrared part of the spectrum, where they are employed for controlling environment and manufacturing processes, as well as in medical devices, strongly challenges current technology and requires more efficient light sources and photodetectors. In this talk, I will review recent progress in mid-infrared (2-6 µm wavelength range) optoelectronics in regards to competing III-V and II-VI materials and nanostructures. In particular, prospects of II-VI-based light emitters will be considered in view of the latest results achieved with the use of molecular beam epitaxy-grown (Hg and Cd) Te nanostructures, where engineering of compositional fluctuations in the alloy seems to advance the emitting properties of these well-known materials to a new level. Concerning III-V materials, I will consider the results of the latest experiments showing the effects of specific non-radiative recombination processes on the properties of narrow-bandgap light emitters, and discuss the prospects that proper optical confinement promises in terms of increasing the efficacy of such devices. Recent experimental findings will be compared to the results of specified calculations of recombination rates in the materials in question.

Biography:

Vladimir G Dubrovskii has received his BS and MS degrees from Saint Petersburg University, and PhD and DSc degrees from Ioffe Institute and Saint Petersburg University in 1986, 1988, 1990 and 2002, respectively, in Condensed Matter Physics. His research interest has been in the areas of condensed matter physics and semiconductor nanostructures. He has authored more than 450 papers in leading technical journals and conferences and 2 monographs. His current research interests are mainly concentrated on nanowire modeling as well as on nucleation theory with applications in physics of semiconductor nanostructures. He is the Head of the Laboratory of Physics of Nanostructures at St. Petersburg Academic University, Head of the International Laboratory “Physics of Epitaxial Nanostructures” at ITMO University and Leading Research Scientist at Ioffe Institute. He is a Member of Steering Committees of International Symposium “Nanostructures: Physics and Technology”, Nanowire Growth Workshop and iNOW Workshop. He is the recipient of a number of academic and university awards and has been a high-level Visiting Scientist at Beijing University of Posts and Telecommunications.

Abstract:

In this talk, I will review recent achievements in monolithic integration of optical III-V nanowires and nanowire-based heterostructures of different types [axial, radial, “quantum dot in nanowire” and crystal phase wurtzite-zincblende (WZ-ZB) heterostructures] on silicon surfaces. The vapor-liquid-solid (VLS) as well as catalyst-free bottom-up approaches to grow conventional III-V and GaN nanowires on silicon can pave new ways for integration of III-V-based optoelectronics with the existing silicon electronic platform. Due to their small dimensions in contact with the substrate and/or within hetero-interfaces, nanowires allow for a radical decrease of the dislocation density and even the dislocation-free growth of dissimilar semiconductor materials and combinations. In particular, I will show how Ga-catalyzed VLS growth of GaAs nanowires by molecular-beam epitaxy produces size and spatially uniform arrays of photonic nanostructures. I will discuss the optical heterostructures within III-V nanowires and their interfacial abruptness compared to planar layers and then will show some impressive results on the nanowire-based microlasers. I will also demonstrate that the comprehensive growth modeling helps to understand and tune very delicate nanowire properties to the desired values that are often unique and inaccessible within standard planar technologies.

Biography:

Vladimir G Dubrovskii has received his BS and MS degrees from Saint Petersburg University, and PhD and DSc degrees from Ioffe Institute and Saint Petersburg University in 1986, 1988, 1990 and 2002, respectively, in Condensed Matter Physics. His research interest has been in the areas of condensed matter physics and semiconductor nanostructures. He has authored more than 450 papers in leading technical journals and conferences and 2 monographs. His current research interests are mainly concentrated on nanowire modeling as well as on nucleation theory with applications in physics of semiconductor nanostructures. He is the Head of the Laboratory of Physics of Nanostructures at St. Petersburg Academic University, Head of the International Laboratory “Physics of Epitaxial Nanostructures” at ITMO University and Leading Research Scientist at Ioffe Institute. He is a Member of Steering Committees of International Symposium “Nanostructures: Physics and Technology”, Nanowire Growth Workshop and iNOW Workshop. He is the recipient of a number of academic and university awards and has been a high-level Visiting Scientist at Beijing University of Posts and Telecommunications.

Abstract:

In this talk, I will review recent achievements in monolithic integration of optical III-V nanowires and nanowire-based heterostructures of different types [axial, radial, “quantum dot in nanowire” and crystal phase wurtzite-zincblende (WZ-ZB) heterostructures] on silicon surfaces. The vapor-liquid-solid (VLS) as well as catalyst-free bottom-up approaches to grow conventional III-V and GaN nanowires on silicon can pave new ways for integration of III-V-based optoelectronics with the existing silicon electronic platform. Due to their small dimensions in contact with the substrate and/or within hetero-interfaces, nanowires allow for a radical decrease of the dislocation density and even the dislocation-free growth of dissimilar semiconductor materials and combinations. In particular, I will show how Ga-catalyzed VLS growth of GaAs nanowires by molecular-beam epitaxy produces size and spatially uniform arrays of photonic nanostructures. I will discuss the optical heterostructures within III-V nanowires and their interfacial abruptness compared to planar layers and then will show some impressive results on the nanowire-based microlasers. I will also demonstrate that the comprehensive growth modeling helps to understand and tune very delicate nanowire properties to the desired values that are often unique and inaccessible within standard planar technologies.

Biography:

Mara Duffles graduated in Physical Therapy from the University Salgado de Oliveira (2007) and a degree in Law from the Catholic University of Minas Gerais (1990). She has obtained Master’s in 2012. She took training in Acupuncture, Clinical Pharmacology and in traditional Chinese medicine, both with the title of specialist, Manual Therapy in Pathologies Craneocervical, Craneomandibular and Facial Pain by Rocabado Method and Manual Therapy by Busquet Physiological Chains Method as well as improvement in laser therapy Low intensity from the Federal University of Minas Mines.

Abstract:

Background: Adhesions commonly occur after abdominal surgery and can cause bowel obstruction, chronic abdominal pain and infertility. Their prevention remains a challenge.

Objectives: To evaluate the effects of the application of low-level lasers on the prevention of adhesions and scarring of the skin after peritoniectomia.

Method: 24 New Zealand breed male rabbits, approximately 2months of age, were randomly divided into 3 groups (n=8): GC—control group not subjected to laser, GL1—group with laser application at a dose of 0.2 J, and GL2—group with laser application at a dose of 3.6 J. All animals performed peritoniectomia. After 14 days postsurgery, the animals were killed and adhesion formation was evaluated qualitatively and quantitatively. Differences were considered significant at P<0.05.

Results: The adhesion formation was observed in100% of the rabbits from groups GC and GL1, as compared to 37.5% of the rabbits from group GL2 (P<0.01). The evaluation of the vascularization and tenacity of adhesions among the groups showed no significant difference. In groups CG and GL1, 72% and 83% of adhesions were verified between visceras, respectively where as in GL2 occurred among abdominal wall. The tensile strength of the skin between the groups was not significant (P=0.3106). The resistance of abdominal wall segments without skin segments between groups GL2 and GC were higher than in GL1 (P=0.01).

Conclusion: Low-level laser is effective in preventing intra-abdominal adhesions in rabbits without compromising strength and healing of the abdominal wall. 

Biography:

Won Bong Lim has completed his PhD from the Department of Oral Pathology and Post-doctoral studies from Chonnam National University in South Korea. He is an Assistant Professor in the Department of Premedical Science, College of Medicine, Chosun University and Director of Research Lab at Department of Orthopedic Surgery in Chosun University Hospital. He has published more than 50 papers in reputed journals of Low Intensity Laser Therapy and Cancer Biology. 

Abstract:

Low-level laser therapy (LLLT)/LED therapy has been proposed as an alternative to conventional osteoporosis therapies. Our aim was to determine the effect of irradiation with a light-emitting diode on receptor activator of NF-κB ligand (RANKL)-mediated differentiation of mouse bone marrow macrophages into osteoclasts, and compare it to alendronate treatment. The surface of cells was irradiated with LED at 5 mW/cm² for 60 minutes in a CO₂ incubator. The differentiation of irradiated and untreated RANKL-stimulated bone marrow macrophages into osteoclasts was evaluated by tartrate-resistant acid phosphatase (TRAP) staining and by molecular methods. These included assessing mRNA expression of osteoclastic markers such as c-Fos, NFATc1, TRAP, OSCAR, MMP9, and cathepsin K; phosphorylation of various MAPKs, including extracellular signal-regulated kinase ERK1/2, P38, and JNK; NF-κB translocation; and resorption pit formation. Results were compared to those obtained with sodium alendronate. Production of reactive oxygen species was measured by a 2ʹ,7ʹ-dihydrodichlorofluorescein diacetate assay. LED irradiation and alendronate inhibited mRNA expression of osteoclast-related genes, such as TRAP, c-Fos, and NFATc1, and reduced the osteoclast activity of RANKL-stimulated bone marrow macrophages. LED irradiation, but not alendronate, also inhibited the production of reactive oxygen species; phosphorylation of ERK, P38, and IκB; and NF-κB translocation. These findings suggest that LED irradiation has an inhibitory effect on osteoclast formation; this effect could lead to reduced bone loss and may offer a new therapeutic tool for managing osteoporosis.

Biography:

Haiyan Fu is an experienced Researcher in Analytical Techniques and Chemometric. She has completed her PhD from Hunan University. She is an Associated Professor and Director of the Department of Pharmaceutical Analysis at South Central University for Nationalities, China.

Abstract:

As a popular detection model, the fluorescence “turn-off” sensor based on quantum dots (QDs) has already been successfully employed in the detections of many materials, especially in the researches on the interactions between pesticides. However, the previous studies are mainly focused on simple single track or the comparison based on similar concentration of drugs. In this paper, a new detection method based on the fluorescence “turn-off” model with water-soluble ZnCdSe and CdSe QDs simultaneously as the fluorescent probes is established to detect various pesticides. The fluorescence of the two QDs can be quenched by different pesticides with varying degrees, which leads to the differences in positions and intensities of two peaks. By combining with chemometrics methods, all the pesticides can be qualitative and quantitative respectively even in real samples with the limit of detection was 2x10-8 molL^-1 and recognition rate of 100%. This work is, to the best of our knowledge, the first report on the detection of pesticides based on the fluorescence quenching phenomenon of double quantum dots combined with chemometrics methods. What’s more, the excellent selectivity of the system has been verified in different mediums such as mixed ion disruption, waste water, tea and water extraction liquid drugs. The results show that this fluorescent “turn-off” mode combined with chemometrics methods is a promising approach for the future study of the detection of pesticides residues.

Biography:

Peter A Bokhan received PhD and DSc degrees in Optics from Tomsk State University, Tomsk, Russia, in 1973 and 1988, respectively. He has been a Principal Scientist at the A V Rzhanov Institute of Semiconductor Physics, Siberian Branch Russian Academy of Science, Novosibirsk, Russia, since 1995. He is an author of more than 180 journal publications, 8 books and 20 patents. His current research interests include laser physics, gas discharge physics, methods of electron beam generation in gases and laser isotope separation.

Abstract:

It is desirable for the ultrafast communications, optical computer, etc., to create the lasing medium with as broad band as possible. To solve this task, the investigations of lasing and luminescence characteristics Si doped Al_xGa_1-xN epitaxial films 0.5…1.2 µm thickness on the sapphire substrate were carried out. The following excitation methods were used: а) by an electron beam with the energy to 20 keV, pulse duration 10 …100 ns; b) second harmonics and summary frequency of copper vapor laser on wave length 255, 271 and 293 nm; c) fourth harmonic of Nd³⁺:YAG laser with wave length 266 nm. In either case, the luminescence spectra are similar and they have an edge band with x-dependent wavelength from 365 nm to 310 nm and a broad band taking over the whole visible spectral range and near infrared one with broad band up to 500 THz. The main characteristics of superradiance in the broad band are presented. The spectral range depends from x and extends from 400 nm to 750 nm at x=0.5 and from 330 nm to 700 nm at x=1. The gain of active media also depends from x and is equal g=70cm^-1 for weak signal (0.7%/µm) for x=0.5 and g=20cm^-1 for x=0.74. The dependences of output power from active media length and pumping power demonstrate three features: a smooth growth at low pumping power or at small active length, then exponential growth and eventually comes to the saturation. The obtained resultants can be used for both the creation of waveguide lasers in a wide range and lasers with the femtosecond pulse duration. 

Biography:

Mahmoud Fallahi is a professor in the college of optical Sciences at the University of Arizona. He received his Ph.D. degree from the University of Toulouse and LAAS-CNRS, in 1988. He joined the National Research Council of Canada in 1989 and became a member of technical staff as a Research Scientist during 1992-1995. He joined the University of Arizona as an Assistant professor in 1995. His research has been extensively published in peer-reviewed scientific journals, reported in invited talks and published in international conference proceedings. He has authored or co-authored several book chapters, patents and invention disclosures. He has served as Conference Chair and Program Committee member in several international conferences in the field of semiconductor lasers and integrated optics. Since August 2014 he has been with the National Science Foundation (NSF) as a Program Director of the photonics program in the ECCS Division of Engineering Directorate. As a Program Director he is promoting and managing translational research in the field of optics and photonics.

Abstract:

High power, tunable two color semiconductor lasers are highly suitable for the new wavelengths generation thanks to various nonlinear conversions. Vertical external cavity surface emitting lasers (VECSELs) are of special interest due to the access to the high intracavity circulating power and wavelength control. In this talk, we will present our recently developed and patented T-cavity VECSEL capable of delivering high power, tunable two color emission will be presented. The T-cavity two-chip VECSEL allows emission of orthogonally polarized high-power collinear outputs of the two wavelengths. By composition and thickness engineering of strain-compensated multi-quantum well InGaAs active layers, a wide range of wavelengths is achieved. Intracavity birefringent filters are then used to facilitate tunability and wavelength separation between two colors. The tunability of the individual VECSEL chips in the collinear two-color T-cavity configuration enables the control of the spectral separation of the lasing peaks. A folded-cavity configuration of such laser is used for high power intracavity second harmonic and sum frequency generation of multi-watt blue and green emissions. Latest results will be reported. 

Biography:

Yanbo Bai has completed his PhD from Northwestern University. His research at Northwestern led to the most efficient and most powerful Quantum Cascade Lasers. His current role at Coherent is to develop more efficient optically pumped semiconductor lasers and explore new wavelength capabilities. He has published more than 40 papers in reputed journals, such as Nature Photonics, Applied Physics Letters, Journal of Applied Physics, etc. He also serves as reviewer for many journals.

Abstract:

Optically pumped semiconductor (OPS) laser has unique advantages over its electrically pumped counterparts. The most prominent one being power scalable without sacrificing the beam quality. Lasing in the fundamental frequency at near infrared with over 100 watts has been demonstrated. Visible power in tens of watts by second harmonic generation and ultraviolet power in several watts by third harmonic generation have been commercialized. In this work, an OPS gain model is developed based on the 8-band kp method. Theoretical and experimental result indicates that this model cans predict the threshold accurately. Temperature dependent simulation allows for the modeling of self-heating and thermal rollover, therefore predicting the achievable output power. Guided by this model, improvement of existing wavelength and expansion of the wavelength coverage are demonstrated.

Biography:

Sigang Yang has received his PhD degree from the Department of Electronics Engineering, Tsinghua University in 2008. He was a Post-doctoral Fellow in the Department of Electrical and Electronic Engineering in the University of Hong Kong. He has joined the faculty of Tsinghua University in August of 2010. He is now an Associate Professor in the Department of Electronic Engineering, Tsinghua University. His research fields include computational electromagnetism, photonic crystal fibers; fiber nonlinearities; fiber based optical parametric amplifications (FOPAs) and oscillators (FOPOs); terahertz wave and frequency comb. 

Abstract:

Light sources operating in the non-conventional wavelength band in which traditional lasers cannot oscillate have attracted great attention recently, since the applications of lasers are extending increasingly into new fields, such as biomedical imaging, spectroscopy and so on. Optical parametric generation in optical fibers refers to a phenomenon where weak spontaneous emission is amplified by the pump wave based on the effect of degenerate four-wave mixing (FWM). It can provide tunable radiation in non-conventional wavelength bands with the advantages of flexibility, low cost and compactness. The gain from parametric process depends on the phase matching condition among the pump, signal and idlers. And the dispersion profile of the gain fiber play a critical role in the phase matching mechanism. Photonic crystal fibers (PCFs) can provide more freedoms to customize its dispersion and nonlinearity, compared with the traditional fibers with doping technology. Especially its zero dispersion wavelengths can be located in nearly any wavelength and it has very large nonlinear coefficient. Thus, the parametric process in PCFs can provide gain in nearly any wavelength band according to the pump wavelength and the dispersion of PCF. Firstly, parametric wavelength conversion with very large span between visible and infrared band is demonstrated based on our homemade PCFs with two zero dispersion wavelengths. The theoretical design guideline is also introduced. Secondly, optical parametric amplifiers and oscillators based on PCFs pumped with 1060 nm band laser pulse are introduced in details. These works show that the optical parametric generation in PCFs is promising to provide light radiation in non-conventional wavelength bands.

Biography:

Peter A Bokhan received PhD and DSc degrees in Optics from Tomsk State University, Tomsk, Russia, in 1973 and 1988, respectively. He has been a Principal Scientist at the A V Rzhanov Institute of Semiconductor Physics, Siberian Branch Russian Academy of Science, Novosibirsk, Russia, since 1995. He is an author of more than 180 journal publications, 8 books and 20 patents. His current research interests include laser physics, gas discharge physics, methods of electron beam generation in gases and laser isotope separation.

Abstract:

The output characteristics of laser essentially depend on power supply pulse duration and its energy. This case is a very important switching characteristic of a device used for short and powerful pulse generation. The subnanosecond breakdown stage in the kivotron, novel switching device with counter-propagating electron beams based on the open discharge in helium, was experimentally studied. It was shown that the fast discharge stage arises when the discharge self-sustaining regime is ensured by the photoelectron emission from the cathodes due to resonant radiation emitted by fast helium atoms that have large Doppler shifts with respect to the line center. Since the excitation cross-section of a helium atom by another fast helium atom increases rapidly with the energy of the fast atom, the duration of the breakdown stage strongly depends on the working voltage in the range 2-10kV and weakly from 15 to 100 kV. The switching time less than 80ps was achieved when discharge circuit loaded to a resistance R_L≥50 Ω. Decrease of R_L down to 10 Ω increases the switching time to about 100ps at 1.5-kA current with current density 120A/cm². A minimum switching time that can be achieved via kivotron design optimization is estimated to be about 35ps. A kivotron has to be used for pumping of different laser, including copper vapor laser, semiconductor lasers, etc. It was demonstrated that in this case it is possible to improve essential laser output characteristics.

Biography:

Luis Gustavo Marcassa has completed his PhD from University of São Paulo and Post-doctoral studies from MIT. He is a Professor at the University of São Paulo. He has published more than 105 papers in reputed journals and has been serving as an Editorial Board Member of Journal of Physics B.

Abstract:

In recent years, there has been an increasing interest of early detection of citrus diseases to prevent great economic losses due contamination of new plants. There are two major citrus diseases: Citrus canker (Xanthomonas axonopodis pv. citri) and Huanglongbing (HLB, Candidatus Liberibacter asiaticus). Both are a serious threat to citrus production worldwide including regions in Brazil and USA. The whole process to confirm the diseases is time consuming and expensive. So, there is a demand for a fast, sensible, and selective method for the rapid detection of citrus diseases. One of these techniques, fluorescence spectroscopy has been investigated as a tool in plant studies, because it has the potential to discriminate different diseases in citrus crops and besides it is nondestructive and nonintrusive to the plant physiology. In the last decade, our group has applied laser induced fluorescence spectroscopy and fluorescence imaging spectroscopy to discriminate diseased samples with similar visual symptoms. Different computational methods were successfully used for the different citrus disease classification. In this work, we will present a review in our work on detection and classification of infected trees with citrus canker, citrus scab, HLB and zinc deficiency. Our recent results show that we obtain a high accuracy when compared either samples with citrus canker and citrus scab (100%), or samples with HLB and zinc deficiency (95%). Furthermore, the sensitivity and specificity obtained for each group is also high. Therefore, we believe that such technique can be applied in the field to detect diseases that have similar symptoms.

Biography:

Milo W Hyde IV received his BS degree in Computer Engineering from the Georgia Institute of Technology, Atlanta, GA, in 2001, and the MS and PhD degrees in Electrical Engineering from the Air Force Institute of Technology, Dayton, OH, in 2006 and 2010, respectively. He is currently an Associate Professor with the Department of Electrical and Computer Engineering, Air Force Institute of Technology. His current research interests include electromagnetic material characterization, guided-wave theory, scattering, and optics. He is a Senior Member of IEEE and a member of SPIE and OSA.

Abstract:

Existing in a state between coherent (e.g., lasers) and incoherent (e.g., incandescent) light sources, partially-coherent beams (PCBs) can be highly directional like a laser while also being resistant to scintillation or speckle. These characteristics make these beams attractive for use in applications such as free-space optical communications, directed energy, manufacturing, particle manipulation, medicine, and video projection. Considering their many potential uses, the study and especially synthesis of PCBs has become a very popular research subject. One of the most interesting developments to arise out of this work is the ability to precisely control beam shape by manipulating spatial coherence. The Air Force Institute of Technology working with New Mexico State University has been heavily involved in this research. We have developed several novel techniques to synthesize PCBs which yield beams of any desired shape. This presentation reviews this recent work in beam shaping using spatial coherence and discusses future research.

Biography:

Milo W Hyde IV received his BS degree in Computer Engineering from the Georgia Institute of Technology, Atlanta, GA, in 2001, and the MS and PhD degrees in Electrical Engineering from the Air Force Institute of Technology, Dayton, OH, in 2006 and 2010, respectively. He is currently an Associate Professor with the Department of Electrical and Computer Engineering, Air Force Institute of Technology. His current research interests include electromagnetic material characterization, guided-wave theory, scattering, and optics. He is a Senior Member of IEEE and a member of SPIE and OSA.

Abstract:

Existing in a state between coherent (e.g., lasers) and incoherent (e.g., incandescent) light sources, partially-coherent beams (PCBs) can be highly directional like a laser while also being resistant to scintillation or speckle. These characteristics make these beams attractive for use in applications such as free-space optical communications, directed energy, manufacturing, particle manipulation, medicine, and video projection. Considering their many potential uses, the study and especially synthesis of PCBs has become a very popular research subject. One of the most interesting developments to arise out of this work is the ability to precisely control beam shape by manipulating spatial coherence. The Air Force Institute of Technology working with New Mexico State University has been heavily involved in this research. We have developed several novel techniques to synthesize PCBs which yield beams of any desired shape. This presentation reviews this recent work in beam shaping using spatial coherence and discusses future research.

Biography:

Masayoshi Tonouchi has received the BS and MS and Dr. E degrees form Osaka University, Japan. He has worked at Osaka University, Kyushu Institute of Technology, Communications Research Laboratory. Currently, he is a Professor in Institute of Laser Engineering, Osaka University and a concurrent Professor of Nanjing University. He has published more than 250 papers, given over 100 invited talks and has been serving as an Associated Editor, Journal of Applied Physics, an international organization Committee Member of IRMMW, and Editorial Board Member of many journals. He chaired many international conferences such as OTST2013.
 

Abstract:

One can observe terahertz (THz) radiation from various kinds of materials, when excited with a femtosecond laser, owing to ultrafast current modulation. THz waves reflect various kinds of properties such as local electric field, particularly ultrafast transient phenomena, in their waveforms. The observation of the THz waveforms enables us to explore ultrafast nature of electronic materials and devices as a THz emission spectroscopy. When one excites the THz emission from a certain substance with the femtosecond optical pulses and visualizes the emission image by scanning the laser beam on it, the resolution of the image is limited by the laser beam diameter rather than THz wavelength. Thus, construction of a laser-THz emission microscope (LTEM) would provide a new tool for material/device science and application. We proposed and have been developing LTEM since 1997. In this talk, we will report the basics of LTEM, and applications for evaluation of solar cells and GaN wafers. 

Biography:

Zhe Wang has his expertise in Laser Diagnostics especially in LIBS. He has completed his PhD from the Pennsylvania State University. He is Associated Professor and Executive Director of the Institute of Simulation and Control for Power System and has been working on Coal Analysis using LIBS for years. 

Abstract:

Laser-induced breakdown spectroscopy (LIBS) has shown great potential in coal analysis, steel analysis, environmental monitoring, etc. Recently, the LIBS community of China has been great expanded and progress has been made to this technology. Low sample-to-sample repeatability of LIBS is the most critical obstacle for accurate quantification and wild commercialization of the technology. In this work, we proposed a set of method to improve both precision (sample-to-sample reproducibility) and accuracy for LIBS quantification. The method includes three steps: 1) the intensities of all spectral lines from every single pulse are converted to a standard state value using a “spectrum standardization” method to reduce the measurement uncertainties to some acceptable levels; 2) the standardized spectra are compared with a large spectral database for identification to check whether the current measured sample is a new sample or has already been in the database with known composition/property information; 3) if the sample is found to be a new sample, a dominant factor based partial least square (PLS) model will be applied to provide quantitative analytical results and the new standardized spectral information and analytic results are inserted into the spectrum database, making the database self-adaptable for future measurement; while if the sample is found to be already in the database, the analytic result will be directly obtained from the database. The proposed method was applied for coal analysis. Results showed that the relative standard deviations (RSD) of carbon for different measurements of the same sample were 0.3%, proving that LIBS is able to provide high reproducibility at least for coal analysis applications. This is the first qualified quantitative application for LIBS with real industrial requirement and the present work has proved the feasibility of LIBS for accurate quantification from technical point of view. The model was also applied for steel elemental analyses using portable LIBS, cement raw material online measurement, and origin identification for jade, with very qualified result for these applications.

Biography:

Jinbo Liu has completed his Doctor degree from Harbin Institute of Technology in 2009 and then worked in the Key Laboratory of Chemical Laser, Dalian Institute of Chemical Physics- CAS. Currently, he is an Associate Professor/Master Director of Chemical Physics.
 

Abstract:

High efficient generation of IR beam by SRS of high pressure H₂, D₂ and CH₄: Stimulated Raman scattering (SRS) is a very effective method to expand the spectrum range of high power laser, especially in the regime of near IR and middle IR. In this paper, SRS of high pressure H₂, D₂ and CH₄ with multiple-pass cell configuration were reported. By the optimization of experimental parameter, such as the pressure of Raman gas and buffer gas, the number of passes, the radium of focus lens, and the radium of curvature mirror, etc., the best conversion efficiency of the first stokes (S1) and the first stokes (S2) was achieved. The lowest S1 threshold was 0.18 MW, and the best S1 conversion efficiency is up to 75%; the lowest S2 threshold was 2.2 MW, and the best S2 conversion efficiency is up to 34%. By the combination of Raman gases and orders of stokes, lasers with wavelength of 1.54μm, 1.56 μm, 1.91 μm, 2.80 μm and 2.92 μm were generated. Experimental results also indicated that lasers with wavelength of 9.8 μm and 22.9 μm were generated.

Biography:

Jinbo Liu has completed his Doctor degree from Harbin Institute of Technology in 2009 and then worked in the Key Laboratory of Chemical Laser, Dalian Institute of Chemical Physics- CAS. Currently, he is an Associate Professor/Master Director of Chemical Physics.
 

Abstract:

High efficient generation of IR beam by SRS of high pressure H₂, D₂ and CH₄: Stimulated Raman scattering (SRS) is a very effective method to expand the spectrum range of high power laser, especially in the regime of near IR and middle IR. In this paper, SRS of high pressure H₂, D₂ and CH₄ with multiple-pass cell configuration were reported. By the optimization of experimental parameter, such as the pressure of Raman gas and buffer gas, the number of passes, the radium of focus lens, and the radium of curvature mirror, etc., the best conversion efficiency of the first stokes (S1) and the first stokes (S2) was achieved. The lowest S1 threshold was 0.18 MW, and the best S1 conversion efficiency is up to 75%; the lowest S2 threshold was 2.2 MW, and the best S2 conversion efficiency is up to 34%. By the combination of Raman gases and orders of stokes, lasers with wavelength of 1.54μm, 1.56 μm, 1.91 μm, 2.80 μm and 2.92 μm were generated. Experimental results also indicated that lasers with wavelength of 9.8 μm and 22.9 μm were generated.

Biography:

Gentaro Watanabe has completed his PhD from the University of Tokyo and Post-doctoral studies from NORDITA, University of Trento, and RIKEN. He has worked at APCTP as a Junior Research Group Leader/Assistant Professor and at the Institute for Basic Science in Korea, he is currently a ZJU Young Professor in the Department of Physics of Zhejiang University.

Abstract:

Interplay between the non-linearity due to the emergence of the superfluid order parameter and the effect of a periodic potential is one of the most important issues of ultracold atomic gases in an optical lattice. However, the study of non-linear phenomena of superfluid Fermi gases in an optical lattice is at a very infant stage unlike that for Bose gases. Appearance of stationary states whose period is not equal to the lattice constant but is a multiple of it, i.e., multiple period states, is a typical non-linear phenomenon. In this talk, we will discuss multiple period states of superfluid Fermi gases in an optical lattice along the crossover between the Bardeen-Cooper-Schrieffer (BCS) and Bose-Einstein condensate (BEC) states, which we have found recently. By solving Bogoliubov–de Gennes equations for a superfluid flow with finite quasimomentum, we find that, in the BCS side of the crossover, the multiple period states can be energetically favorable compared to the normal Bloch states and their survival time against dynamical instability drastically increases, suggesting that these states can be accessible in current experiments, in sharp contrast to the situation in BECs.

Biography:

Binayak S Choudhury is a Professor of Mathematics, Indian Institute of Engineering Science and Technology, Shibpur, West Bengal, India. He obtained his PhD degree in Applied Mathematics from University of Calcutta in 1995. He has published about 200 research papers in Mathematics and Physics. He has guided 14 PhD students. His areas of research interest include Functional Analysis, Quantum Information Theory and Cosmology.

Abstract:

It has been established through research activities over the last three decades that it is possible to make communications using quantum mechanical resources. A pioneering quantum communication protocol appeared in the work of Bennet et. al in 1993  which is known as quantum teleportation protocol. It is a process for transferring information through entangled channels. The work was followed by a large number of research works focusing on the extension of the process as well as for inventing protocols of similar types for performing various jobs of information and state transfer. There have been experimental realizations of some of these protocols. At the heart of these process lies the idea of quantum entanglement. The idea of entanglement can be traced back to the works of Einstein, Podolsky and Rosen in 1935. Its potential applications have been discovered during last two decades. There are various types of entanglements between two or more parties who, in the contexts of quantum communication, are the senders, receivers and possible controllers of the process. Here we present some  teleportation protocols where the purpose is to transmit multiqubit entangled states. We present the use of quantum channels which are robust in the noisy environment. Noise is a  serious concern for all communication systems. This can create devastation in the communication process. For that purpose we present the use of concatenated channels which are more stable against noise. Our protocols are perfect teleportation protocols, that is, there are no cases of failures.