Day 3 :
Keynote Forum
Konrad Altmann
LAS-CAD GmbH, Germany
Keynote: Embedding the photon with its relativistic mass as a particle into the electromagnetic wave explains the Gouy phase shift as an energetic effect
Time : 09:15-09:55
Biography:
Konrad Altmann has completed his PhD in Physics from the Ludwig-Maximilian University of Munich, Germany, at 1975. The issue of his thesis was the quantum mechanical description of molecular spectra. For this work, he obtained the marking "with excellence". From 1976 to 1991 he was with the industrial company
Messerschmitt-Bolkow-Blohm and developed a computer program for the description of a gas dynamic CO2 laser. From 1991 to 1993 he was with the German Aerospace and developed computer programs and published papers concerning laser beam propagation in the atmosphere. In 1993 he founded the company LAS-CAD GmbH with the purpose to integrate different simulation tools, necessary for the analysis of the multi-physics interaction in solid-state lasers, into the commercial program LASCAD. This program provides the laser engineer with the ability of a quantitative understanding of the complicated effects in laser systems. He has over 25 years of progressively responsible experience in computational physics especially in the fi eld of optics. He wrote more than 40 scientifi c publications in molecular physics, propagation engineering and laser technology and applied for 38 patents of which 15 have been granted. He also wrote programs for the simulation of laser beam propagation in the atmosphere. In 2014 he was becoming Adjunct Professor of the National Engineering Center for DPSSL of the Chinese Academy of Science.
Abstract:
A new aspect concerning the relationship between a photon and electromagnetic wave has been developed by considering the question why the energy and the mass density of an electromagnetic wave described by m=E/c² are propagating in the same direction. For instance, in optical resonators, the energy density usually propagates along curved lines. However, according to Newton's first law the mass density should propagate along a straight line if no force is exerted it. In order to solve this problem, which represents a contradiction between fundamental physical laws, the assumption has been made that a transverse force is exerted on the mass density and in consequence on the mass of the photons forcing them to follow the propagating energy density. This force has been computed by considering the infi nitesimal change of the normalized Poynting vector with respect to an infi nitesimal propagation step. Integration of the negative value of this force along the curvature of the phase front shows that the photon is moving within a transverse potential. Th is potential allows describing the transverse quantum mechanical motion of the photon by the use of a Schrodinger equation which is identical with the Schrodinger equation describing the motion of the electron, except that the mass of the electron is replaced by the relativistic mass of the photon. In this way, it could for the first time be shown that the Schrödinger equation is also describing the motion of a particle which has no rest mass. The eigensolutions χnm(x,y,z) of this Schrodinger equation allow to compute the probability density |χnm(x,y,z)|² of the photons propagating with an electromagnetic wave. Th e obtained results have been verifi ed for the case of the plane, the spherical and the Gaussian wave. In case of a Gaussian wave it could be shown that the probability density |χnm(x,y,z)|² )|² of the photon computed in this way is in full agreement with the normalized local intensity provided by paraxial wave optics for a Gaussian mode of order n,m. Also, the Guoy phase shift could be computed by the use of this particle picture in full agreement with the result obtained by the use of wave optics. Moreover, this particle picture allows explaining the Guoy phase shift , which so far has only been considered as a phase shift without any further physical meaning, as an energetic eff ect. It could be shown that due to the Gouy eff ect the axial energy of the photon is reduced with the consequence that the total energy of the photon turns out to be the sum of this reduced axial energy and the energy of the transverse quantum mechanical motion of the photon as obtained as energy eigen solution of the Schrodinger equation.
Keynote Forum
Kaiwei Wang
Zhejiang University, China
Keynote: 5 years of implementing light to help the visually impaired at the National Optical Instrument Engineering Technology Research Center
Time : 09:55-10:35
Biography:
Kaiwei Wang is the Deputy Director of the National Optical Instrument Engineering Research Center at Zhejiang University. He received a BS degree in 2001 and a PhD degree in 2005 both from Tsinghua University. He started Postdoctoral research at the Center of Precision Technologies (CPT) of Huddersfi eld University, funded by the Royal Society International Visiting Postdoctoral Fellowship and the British Engineering Physics Council. He joined Zhejiang University in February 2009 and has been mainly researching on Intelligent Detection Device for Passive Fiber Components and Visual Assisting Technology for the Visually Impaired since then. With years of hard work, he was awarded the "521 Plan" expert in Hangzhou, owns 34 patents and has published more than 100 research papers.
Abstract:
According to the World Health Organization, 285 million people around the world are estimated to be visually impaired and 39 million of them are blind. It is rather challenging for visually impaired people (VIP) to navigate through obstacles and avoid various hazards such as water puddle and approaching vehicles in unknown environments. At the National Optical Instrument Engineering Technology Research Center, a number of revolutionary techniques and apparatus have been explored to address the above problems. An eff ective approach is studied to expand the detection of traversable area based on an RGB-D sensor, which is compatible with both indoor and outdoor environments. Th e depth image of is enhanced with IR image largescale matching and RGB image-guided fi ltering. A polarized technique is implemented in order to detect traversable areas and water hazards by adequately considering polarization eff ects. A real-time crosswalk detection algorithm, adaptive and consistency aextraction analysis (AECA), is proposed to detect and remind the position of crosswalks at urban intersections. Compared with existing algorithms, which detect crosswalks in ideal scenarios, the algorithm performs better in challenging scenarios, such as crosswalks at far distances, low contrast crosswalks, pedestrian occlusion, various illuminances and the limited resources of portable PCs. A real-time Pedestrian Crossing Lights (PCL) detection algorithm for the visually impaired is also proposed. Diff erent from previous works which utilize analytic image processing to detect the PCL in ideal scenarios, the proposed algorithm detects PCL using machine learning scheme in the challenging scenarios, where PCL have arbitrary sizes and locations in the acquired image and suff er from the shake and movement of the camera. Up to date, tens of thousands visually impaired individuals are benefi ting from these technologies.
- Applications and Trends in Optics and Photonics | Optical Physics
Location: Colombard
Chair
Caterina Gaudiuso
Università degli Studi di Bari, Italy
Co-Chair
Yutaka Fukuchi
Tokyo University of Science, Japan
Session Introduction
Sunggoo Cho
Semyung University, South Korea
Title: Parabasal formulas and their applications
Biography:
Sunggoo Cho completed his PhD in the year 1989 from University of Maryland, College Park, USA. As a student of the physics department, he wrote his PhD thesis on “supermanifold” under the supervision of Dr P Green in the department of mathematics. After Post-doctoral research at Sogang University, South Korea, he had worked as a Professor at the Department of Physics of Semyung University from 1991 to 2005 as a pure mathematical physicist. Now he is a Professor at the School of Computer Science of Semyung University teaching game programming and deep learning. He has developed a couple of commercial software with a team of students. In addition, he is a researcher and developer at the Light and Math Inc. at Semyung University and has more than 20 patents. He has also developed several computer programs for optical applications such as interferometer program with noisy fringe patterns for Prooptics Inc. in South Korea. He has executed more than 15 commercial projects for several companies. He is currently working on deep learning and its applications to optics and computer vision.
Abstract:
Parabasal theory is a technique in geometrical optics that describes the behavior of light rays located near some defined base ray rather than the optical axis. In this work, we are concerned with parabasal rays which lie in a sufficiently small neighborhood of a chief ray and develop some formulas for parabasal quantities of the chief ray. Parabasal quantities of a chief ray are shown to be intimately related to the coeffi cients of fi rst order differential equations of the chief ray. Using the relations, we derive parabasal formulas containing parabasal refractive indices and parabasal powers from the first order differential equations. Th ese parabasal formulas turn out to be decoupled diff erential equations of the fi rst order diff erential equations so that highly coupled diff erential equations for a chief ray can be solved systematically. In addition, we apply parabasal formulas to the paraxial region by taking the limits of the formulas. Th ese limits give necessary conditions expressed in terms of Gaussian brackets for various initial design requirements of optical lens systems. Th ose necessary conditions do not seem to be derivable by using only paraxial theory without parabasal approaches developed in this work.
Guo-Dung J Su
National Taiwan University, Taiwan
Title: Design of a high-efficiency narrow spot headlampwith distributed LEDs
Biography:
Guo-Dung J Su had his BS degree from National Taiwan University in 1994. He then joined the University of California, Los Angeles and received and his MS and PhD in electrical engineering in 1998 and 2001 respectively. His Doctoral research interest is related to MEMS scanners with a fl at mirror surface for active optical alignment and micromirror arrays for adaptive optics applications. Since 2004, he became an Assistant Professor at Graduate Institute of Photonics and Optoelectronics and Department of Electrical Engineering of National Taiwan University. His current researches include Optical system design, MEMS devices for optical communications, compact optical imaging systems and surface plasmon phenomenon on nanoparticles.
Abstract:
In this talk, we present a narrow spot headlamp system of the dual half circular parabolic aluminized refl ector (PAR). This system has a property that each of the half-circular PAR contains fi ve high-effi ciency and small package light emitting diode (LED) chips with 180o rotational symmetry. Concerning traffic safety, the design criterion of train headlamp is to meet the code of Federal Regulations (CFR). In terms of the forecast of illuminated position on a screen, analytic derivation has been developed to study the optical path of a ray which is perpendicular to and emitted from the center of the LED chip. This ray stands for the main emitted ray of the LED chip and it is inside of the illuminated spot by the LED source on the screen. Therefore, we can analyze design systematically for determining where the LED chips ought to be placed in the PAR reflector for minimizing electricity consumption while satisfying the reliability constraints on train headlamp to ensure traffic safety. Compared to a typical train headlamp system with incandescent or halogen lamp needing several hundred watts, the proposed system only uses 20.18W to achieve the luminous intensity requirements. Compared with the typical train headlamp system incorporating incandescent or halogen lamp with a power rating about 200 to 350W, the proposed system only uses 20.18W to achieve the luminous intensity requirements. If the train headlamp turns on 8 hours a day, one year can save electricity about 584kWh (=0.2kW8h/d365d). If electric power is generated from crude oil, according to the estimation of 0.26kg CO2/kWh in the literature, the proposed approach can eff ectively lower down about 152kg CO2 emission per year for a single lamp.
Yong Han
Sun Yat-Sen University, China
Title: The Asian dust and agricultural biomass burning aerosol from the ground-based Lidar and satellite measurements in China: Transport, optical properties and impacts on regional air quality
Time : 11:55-12:25
Biography:
Yong Han has completed his PhD (Major: Optics) in the year 2007 at the age of 32 years from the key lab of atmospheric optics, Anhui Institute of Optics and Fine Mechanics, Hefei Institute of Physical Science, Chinese Academy of Sciences. He has completed his post-doctoral (Major: Atmospheric Sciences) in the year 2010 at the age of 35 years from Key Laboratory of Middle Atmosphere and Global Environment Observation (LAGEO), the Institute of Atmospheric Physics, Chinese Academy of Sciences. Before 2017, he was an associate professor at the School of Atmospheric Science, Nanjing University. Now, he is a Professor of School of Atmospheric Sciences, Sun Yat-Sen University, an important scientific and talent training university. He teaches the undergraduate core course earth atmosphere integrated exploration and graduate courses radar and satellite. He has published more than 55 papers in reputed journals, two international invention patents, monographs of the editor in chief (the Principle and Method of Detection in Atmospheric Science) and has been serving as an member of the Atmospheric Exploration and Instrumentation Committee of China Meteorological Society, Youth Director of China Particle Society, Specialized Committee Member of Jiangsu Meteorological Society and Director of Jiangsu Particle Society, China, etc. His research interests are the study of Atmospheric Physics and Atmospheric Exploration, Atmospheric Remote Sensing and Atmospheric-ocean Optics, Atmospheric Composition and Observation Scientific Instruments.
Abstract:
The optical properties, time-height distribution and impact on the local air quality from a heavy Asian dust transport episode are investigated with a synergistic ground-based, satellite sensors and model on May 2011 in Nanjing city (32.05°N,118.78°E, 94m ASL), China. Two dust layers located in the planetary-boundary-layer (PBL, <2.5km) and free troposphere (3–6km) are observed by a Polarization Raman-Mie Lidar. Diff erent transport paths originating from the Gobi deserts and Taklimakan deserts are demonstrated by the NOAA HYSPLIT, NAAPS models and NASA satellites (MODIS and CALIPSO) imageries. Th e dust aerosol layer shows the depolarization ratios at 0.1–0.2 and strong extinction coeffi cients attaining 1.0km-1 at 532nm and the Lidar ratios of dust are 47.3–55sr below 2.5km altitude. During this dust intrusion period, the aerosol optical depths (AOD) dramatically increase from 0.7 to 1.6 at 500nm whereas the Angstrom exponents decrease from 1.2 to 0.2 according to the Cimel-sunphotometer measurement. Meanwhile, both surface PM10 and PM2.5 concentrations show similar temporal variation and a signifi cant increase with the peak value attaining 767ïg/m3 and 222ïg/m3 respectively. Regional influences of the transported dust are further illustrated by the AERONET-sunphotometer observations at Taihu and Xianghe sites (downwind and upwind from Nanjing), satellites MODIS, CALIPSO and model products in east China. In addition, we also discussed the agricultural biomass burning (ABB), which has been of particular concern due to its influence on air quality and atmospheric radiation, as it produces large amounts of gaseous and aerosol emissions. This study presents an integrated observation of a signifi cant ABB episode in Nanjing, China during early June 2011, using combined ground-based and satellite sensors. The time-height distribution, optical properties, sources and transport of smoke, as well as its impacts on air quality are investigated. Lidar profi les indicate that the smoke aerosols are confi ned to the planetary-boundary-layer (PBL) and have a depolarization ratio of less than 0.08. Th e aerosol optical depth (AOD) increases from 0.6 to 3.0 at a wavelength of 500nm, while the Angstrom exponent varies from 1.0 to 1.6. Th e aerosol single scattering albedo becomes smaller (0.87-0.8) at 675-1020nm and shows a decreasing trend from the wavelength of 440nm to 1020nm, indicating more absorbing aerosols. The absorption Angstrom exponent (0.7) is smaller than 1.0, which may indicate the aged smoke particles mixed or coated with the urban aerosols. By combining MODIS fire, AOD, CO from AIRS and NO2 from OMI products, the ABB sources are identified in mid-eastern China. Surface PM10 and PM2.5 show a dramatic increase, reaching 800ïg/m3 and 485ïg/m3, respectively.`
Xiahui Tang
Huazhong University of Science and Technology, China
Title: Research of the pico-second CO2 laser amplifier based on sequence band gain spectrum
Biography:
Tang Xiahui is a professor and doctoral supervisor of School of Optical and Electronic Information at Huazhong University of Science and Technology. He is presently the vice-director of the National Engineering Research Center for Laser Processing and he is the executive member of the council of Hubei mechanical engineering society and laser processing committee of the Chinese Optical Society, the vice-chairman of Laser Institute of Hubei Province, the editor of “Laser Technology” and “Applied Laser”. His interested areas are high power CO2 gas Laser, high power laser processing systems integration, welding, brazing, cutting and surface engineering. He published more than 60 papers in the domestic and foreign academic journals, more than 20 papers were SCI, EI, ISTP included and Obtained 5 Chinese invention patents. He received Hubei Science and Technology Progress Award in 2004 and Ministry of Education, National Science and Technology Progress Award nominations in 2005. He has fi nished the MOST National “Fifteen” Scientifi c Technological Research Plan, “Eleventh Five” major scientifi c and technological support plan, Doctoral Fund of Ministry of Education, Hubei Province “Eleventh Five-Year” key scientifi c and technological and NSFC, respectively. Further, he undertook nearly 60 enterprises of science and technology projects.
Abstract:
When the ultra-short laser pulse is used for the plasma acceleration, the energy transferring to the charged particle is proportional to the product of the field intensity and the square of the wavelength. Due to its mid-infrared wave band(10.6μm), CO2 laser is likely to be one of the most important next generation light source for the laser acceleration of proton and ion. However, due to the discretization and narrow bandwidth of the gain spectrum of CO2 molecules, it is hard for the chirped pulse amplifi cation being used for the CO2 laser. Th is project proposes to increase the gain of CO2 molecules sequence band using optical pumping and compact the gain spectrum by means of overlapping gain spectrum of sequence band and normal band to solve the problem, realizing pico-second CO2 pulse amplifi cation at quasi-continuous spectrum. The team will carry out the researches about the absorption spectrum of sequence band, the energy relaxation at each rotational level of the optical pumped sequence band, the coherent amplifi cation process of diff erent spectrum of the input pulse in the different gain band series both theoretically and experimentally. Establishing a synthesis analytical model of a quasi-continuous spectrum CO2 laser amplifi cation matching electro-optic pump, roundly analyzing infl uence of gain of CO2 sequence band on performance characteristics of the amplifi er, building pulse discharge CO2 laser amplifi er with innovative structure and high effi ciency pumped by solid-state laser, obtaining laser output at ps-mJ level, Laying the theoretically and experimentally foundation for picosecond-Terawatts CO2 laser system.
- Young Researchers Forum
Location: Colombard
Chair
Kaiwei Wang
Zhejiang University, China
Session Introduction
Zhuoyue Hu
ShangHai Institute of Technical Physics of CAS, China
Title: A Study of camera on orbit radial calibration based on blackbody and infrared calibration stars
Biography:
Zhuoyue Hu has completed her undergraduate study in the year 2016 from UESTC(University of Electronic Science and Technology of China). She is studying in the SITP(Shanghai Institute of Technical Physics of the Chinese Academy of Sciences) for a PhD.
Abstract:
In view of the radiometric calibration of large aperture optical systems, a parallel light coupling method is proposed to achieve non-uniformity correction and radiometric calibration through the internal blackbody into the optical path. The sensor consists of two parts, the front optical system and the rear optical system. Between the front optical system and the rear optical system is connected by parallel light, which is the characteristic of this calibration system. Its calibration system includes image space blackbody and calibration mirror. In this paper, the relative radiation calibration is realized by an internal blackbody. We establish a response database with integral time and blackbody energy as a variable and a nonlinear nonuniformity correction algorithm based on variable integration time and variable energy are adopted to achieve the relative radiometric calibration of the image. Th rough the non-uniformity correction algorithm, we get the result which is better than 0.2%. It shows a better result than the two-point correction and multi-point correction. We also use the star and internal blackbody to monitor the stability of the camera, we chose the star which satisfi es the Radiation theory, it is easy to find the star and simplify the process. By comparing with the internal blackbody calibration, the calibration method based on the WISE star table can achieve the calibration accuracy better than 10%. We found that the system stability result of the back optical is within 3% and the front optical is within 5% for 8 months. According to the requirement of calibration precision, the frequency
of calibration is designed.
Tong Hoang Tuan
Toyota Technological Institute, Japan
Title: Suppressing 1.06-μm spontaneous emission of Neodymium ions using a novel tellurite all-solid photonic bandgap fiber
Biography:
Tong Hoang Tuan was born in Ho Chi Minh City, Vietnam, in 1985. He received his MS degree in Applied Physics from the University of Science, Ho Chi Minh City, Vietnam in 2010 and PhD degrees in Future Industry-Oriented Basic Science & Material Engineering from Toyota Technological Institute, Nagoya, Japan in 2015. Since then, he joined the Laboratory of Optical Functional Materials, Toyota Technological Institute, as a post-doctoral fellow. His special technical skills are involved in glass material development, fi ber characterization and fabrication using highly nonlinear materials. In 2017, he received the KAKENHI research fund supported by Japan Society for the Promotion of Science (JSPS). His current research interests include the fabrication and characterization of chalcogenide and tellurite buffer-embed hybrid microstructure optical fi bers for broadband mid-infrared supercontinuum generation, fi ber optical parametric amplifi cation and frequency comb generation, the dynamic photonic bandgap control of novel all-solid photonic bandgap fi bers for ultrafast optical modulation, the hollow-core photonic crystal fibers and the infrared optical image transport in novel tellurite optical fi bers with transversely disordered refractive index profi le.
Abstract:
In recent years, the development of high capacity and broad transmission optical systems and devices for global telecommunication networks is rapidly increasing due to the explosive spread of telecommunication devices such as smartphones and computers. Along with the development of broadband optical systems, the demand for optical amplifiers at many diff erent wavelengths in the telecommunication range are also growing. Although Erbium-doped fiber amplifiers (EDFA) are widely used as gain media for wavelength division multiplexing (WDM) systems, their gain bandwidths are as narrow as 30nm from 1530 to 1560nm. In a nearby wavelength range, optical fi ber amplifiers operating near 1.3μm in the telecommunication band where conventional single-mode fi bers have low-loss and low dispersion are very attractive. Among several active rare-earth ions that have been investigated for optical fiber amplifi ers operating near the 1.3μm spectral region, Nd3+ is a potential candidate for compact and highly effi cient optical fi ber amplifi ers even with a short fi ber length of a few centimeters due to its 4F3/2→4I13/2 transition. However, the use of the 1.3μm emission in a practical Nd3+-doped fi ber has faced with several problems. One of its major problems is the presence of competing amplifi ed spontaneous emission (ASE) at 1.06μm due to the 4F3/2→4I11/2 transition whose branching ratio is about 5 times larger than that at 1.3μm. In order to realize a practical optical amplifi er device at 1.3μm, the ASE at 1.06μm must be fi ltered out. In this work, we propose a tellurite all-solid photonic bandgap fi ber (ASPBGF) to fi lter out the competing emission at 1.06μm which is most prominent in the emission spectrum of the Nd3+ ion. A novel Nd3+-doped tellurite ASPBGF is fabricated by using our developed tellurite glasses which have high compatibility of thermal properties and their refractive index diff erence is 0.096 at 1320nm. The fiber is designed with 4 layers of high-index rods to have low confi nement loss. Th e measured transmission spectrum of a 2.2cm long section of the fabricated fi ber exhibits high transmission bands near 0.75 and 1.33μm (about -20dB and -19dB) and a low transmission band in the vicinity of 1.06μm which is about -27dB. By using our fabricated Nd3+-doped tellurite ASPBGF, it is demonstrated for the fi rst time that the 1.06μm emission peak due to the 4F3/2→4I 11/2 transition of Nd3+ ions is greatly suppressed about 12 times as compared to that obtained by using a bulk samples with the same doping concentration.
Biography:
Peiqi Zhou has completed his Bachelor's degree in the year 2016 at the age of 22 years from Wuhan University, Wuhan, China. He is now a PhD student of Prof Xingjun Wang from Peking University, Beijing, China. He has published about 2 papers on international journals and conference proceedings.
Abstract:
In recent years, erbium silicate compound has aroused considerable research as erbium-based materials for small size and high gain light sources in silicon photonics integration, since it contains a high erbium concentration that has no insolubility problem. In addition, ytterbium cations are usually added to the erbium silicate to prevent neighboring erbium ions from causing cooperative upconversion and also act as sensitizers. Methods have been utilized for depositing erbium-ytterbium silicate fi lms include the sol-gel method, sputtering and pulsed laser deposition. Compared with other deposition methods, magnetron sputtering has the advantages of fast deposition rate, high purity, good compactness, good uniformity and strong controllability which has gained rapid development and wide application. There are three main sputtering methods for erbiumytterbium silicate fi lms: co-sputtering, multi-layer alternating sputtering and mixed-target sputtering. Although each of them has its own advantages and disadvantages, their systematical researches and comparisons are not enough. In this paper, a series of erbium-ytterbium silicate fi lms with diff erent compositions were prepared by co-sputtering, multi-layer alternating sputtering and mixed-target sputtering. Several analysis and optimization of the fi lms were given to systematically compare three diff erent sputtering methods, which includes the photoluminescence intensity, crystal structure and luminescence lifetime. The results have laid the foundation for the erbium silicate light source devices preparation.
Hehai Fang
Shanghai Institute of Technical Physics, China
Title: Mid-infrared single InAs nanowire metal-semiconductor-metal photodiodes
Biography:
Hehai Fang received his Bachelor degree with honors in condensed matter physics from Nankai University, China, in 2014. He is now pursuing a PhD degree in Microelectronics and Solid-State electronics at the Shanghai Institute of Technical Physics (SITP), Chinese Academy of Sciences (CAS). He got the National Scholarship for outstanding PhD students in 2017. His research interests are in fabrication and characterization of infrared photodetectors based on low dimensional materials, including nanowires, 2D materials and nanostructured semiconductors with narrow bandgaps.
Abstract:
Indium arsenide nanowires (InAs NWs), have been widely researched in recent years together with other III-V semiconductor NWs like InP, GaN, InSb etc. With a high mobility and a direct narrow bandgap (approximately 0.35eV), InAs NWs seem to be more appropriate for applications of high-speed electronic components and broad-spectrum detection media. Photodetectors based on single InAs NW and NW arrays have been successfully fabricated and exhibit a good photoresponse. Research has identified two diff erent photodetection mechanisms for single InAs NW photodetector, which are positive photoresponse (PPR) and negative photoresponse (NPR) respectively. Th e diff erence between these two mechanisms is that the latter is a phenomenon induced by surface states similar to a photo-gating layer (PGL) trapping hot electrons and seems to work only when the energy of an incident photon is much higher than the bandgap of InAs. For NPR, an ultrahigh photoconductive gain of -105 and a response time of less than 5ms have been achieved. While for PPR, the responsivity and detectivity reach 5.3×103A/W and 2.6×1011 Jones, which is also a high performance. However, most reported work about InAs NW-based photodetectors is limited to the visible waveband. Although some work shows the certain response for near-infrared light, the problems of large dark current and a small light on/off ratio are unsolved, thus signifi cantly restricting the detectivity. Here in this work, a novel “visible light-assisted dark-current suppressing method” is proposed for the fi rst time to reduce the dark current and enhance the infrared photodetection of single InAs nanowire photodetectors. Th is method eff ectively increases the barrier height of the metal-semiconductor contact, thus signifi cantly make the device a Metal-Semiconductor-Metal (MSM) photodiode. Th ese MSM photodiodes demonstrate broadband detection from less than 1 μm to more than 3μm and a fast response of tens of microseconds. A high detectivity of ~1012 Jones has been achieved for the wavelength of 2000nm at a low bias voltage of 0.1V with the corresponding responsivity of as much as 40A/W. Even for the incident wavelength of 3113nm, a detectivity of ~1010 Jones and a responsivity of 0.6A/W have been obtained. Our work has achieved an extended detection waveband for single InAs NW photodetector from visible and near-infrared to mid-infrared. Th e excellent performance for infrared detection demonstrated the great potential of narrow bandgap NWs for future infrared optoelectronic applications.
Ciro Dantas Soares
University of Campinas, Brazil
Title: In vivo experimental models of wound healing under the influence of photobiomodulation therapy
Time : 15:05-15:25
Biography:
Ciro Dantas Soares has completed his MSc in the year 2015 at the age of 22 years from University of Campinas, Brazil. Currently, he is PhD training in progress in Oral Pathology of University of Campinas and LA Biomedical Research Institute. He has published more than 20 papers in reputed journals and has been serving as an editorial board member of repute.
Abstract:
Photobiomodulation therapy (PBMT) is the most recent term for the Low-Level Light Th erapy in the MeSH data. As stated by Anders et al. photobiomodulation is defi ned as “A form of light therapy that utilizes non-ionizing forms of light sources, including lasers, LEDs and broadband light, in the visible and infrared spectrum. It is a nonthermal process involving endogenous chromophores eliciting photophysical (i.e. linear and nonlinear) and photochemical events at various biological scales. This process results in benefi cial therapeutic outcomes including but not limited to the alleviation of pain or infl ammation, immunomodulation and promotion of wound healing and tissue regeneration”. The use of PBMT in wound healing lacks mechanistic in vivo assays to determine the pathways activated during the diff erent phases of repair. We will present new data regarding the expression of fi broblast growth factors (FGF) under skin and bone wounds treated with various sources of PBMT. It was demonstrated that PBMT modulates the levels of basic FGF, particularly and consequently, acts activating important pathways of angiogenesis, cell survival and proliferation in models of skin and bone wound healing. In addition, PBMT improves bone repair in female rats with osteoporosis by decreasing the number of neutrophils, monocytes and osteoclast. In summary, the modulation of FGF2 seems to be an important step in the PBMT-based repair and also PBMT improves wound healing by enhancing neocollagenesis, increasing the number of new vessels formed in the tissue (neoangiogenesis) and modulating matrix metalloproteinase-2 expression and as expected, PBMT stimulated bone repair in female rats with osteoporosis and slightly decreased the infl ammatory response.
- Poster Presentations
Location: Colombard
Chair
Sunggoo Cho
Semyung University, South Korea
Session Introduction
Yuzhen Liang
Xiamen University of Technology, China
Title: Reducing radiation loss of near zero-index metamaterials
Biography:
Yuzhen Liang hails from Xiamen, China. She is currently an undergraduate student of photoelectric information science and technology at the Xiamen University of Technology. Her industry experience includes working as an optical assistant at Xiu Yu Incorporated in Taiwan. In this capacity, she helped develop ultra short-focus projection and laser projection technology. At the same time, she worked on the development of automated vehicle systems with regards to visual recognition and produced a smart mattress care system. Her most recent work focuses on the optical engineering of a new keyboard projector.
Abstract:
Optical metamaterials can achieve an unconventional eff ective index of refraction by engineering the geometry of the building blocks. In extreme cases, the eff ective index can approach zero, resulting in infi nite phase velocity and spatial wavelength. However, because of the zero index corresponds to an electric monopole mode and two magnetic dipole modes degenerating at the center of the Brillouin zone, which is innately above the light line, opening a loss channel to the direction perpendicular to the substrate, i.e. the guided wave propagating within the zero-index metamaterial can couple to a planewave radiating in the out-of-plane direction (the direction perpendicular to the substrate). Here we eliminate this out-of-plane radiation loss via the destructive interference between the plane waves radiating upward and downward, forming a bound state in the continuum. A zero-index metamaterial design with a refl ector that reduces radiation loss through the destructive interference of multiple lossy channels, resulting inbound states in the continuum. Th e design includes a silicon pillar array and a planar reflector. By adjusting the distance between the refl ector and the pillars, out-of-plane radiation can be eliminated completely. However, for near zero-index metamaterials (ZIMs), there is no similar design and method to reduce the out-ofplane radiation losses. We design a low-loss near zero-index metamaterial composing of an array of silicon pillars without a reflector. Under an in-plane TM excitation, the pillars support two Bloch modes at the center of the Brillouin zone: an axial electric monopole mode, and a transverse magnetic dipole mode. By adjusting the radius and pitch of the pillar array, we can achieve the degeneracy of these modes at the center of the Brillouin zone and a given operating wavelength, in our case 1525nm.
Hye Mi Cho
Korea Institute for Rare Metal, Republic of Korea
Title: Synthesis and chariterization of CdSe quantum dots of phosphine-free colloidal method under various conditions
Biography:
Hye Mi Cho had a BS in Materials Engineering and a Master of Ceramic Engineering degree. So, as a structural analysis expert, I am doing analysis work to help research.
Abstract:
Recently, quantum dots have been investigated as promising optoelectronic materials because of its unique optoelectronic properties and high stability compared with bulk material by quantum confi nement eff ect. Quantum dots have been studied to solve the limitations of commotional optoelectronic device. For example, the luminescence wavelength can be shift ed to a visible wavelength range with quantum dots. Th erefore, quantum dots optoelectronics can be applied into not only biochemical applications but also light emitting diodes (LEDs), laser and fl uorescent biological label. The composite semiconductor nanocrystals such as CdS, CdSe and ZnSe have been studied for photoluminescent quantum dots materials. Above all, CdSe is advantageous materials because it has bright luminescence in the visible range of the optical spectrum and easily fabricable in well-dispersed nano-sized crystals. The properties of CdSe quantum dots core such as reaction temperature, concentrations and time can be varied using the synthetic parameters. The most of cases, CdSe quantum dots were synthesized by a colloidal process with phosphine (PH3) precursor such as TOP, TOPO and TBP. However, conventional colloidal methods with PH3 were suitable, hazardous and pollutive. In this study, quantum dots are successfully synthesized using phosphine-free colloidal method under various conditions is confi rmed to control surface properties. In order to evaluate the size dependence of CdSe crystal, synthesis temperatures were changed from 2400C to 3000C and precursor ratio (Cd:Se) was controlled. The optical properties of the synthesized CdSe quantum dots were confi rmed using photoluminescence (PL). Th e microstructure and phase developments were measured by transmission electron microscopy (TEM) and X-ray diff ractometer (XRD) respectively.
Jinwoo Lee
Seoul National University, Korea
Title: Nanowire-on-nanowire: All-nanowire electronics by on-demand selective integration of hierarchical heterogeneous nanowires
Biography:
Jinwoo Lee is currently a PhD candidate at Seoul National University in South Korea after he completed his master degree at KAIST. His research of interest is laser-induced material growth, laser sintering of materials for functionalization and fabrication of energy storage/harvesting device.
Abstract:
Exploration of the electronics solely comprised of bottom-up synthesized nanowires has been largely hindered due to the complex multistep integration of diverse nanowires. In this research, we report the demonstration of on-demand selective laser integration of secondary heterogeneous branched metal oxide NWs on a primary backbone metal NW in a highly selective manner based on a heater-assisted laser-induced hydrothermal growth (LIHG) process. Th e most widely studied NWs, silver (Ag) and zinc oxide (ZnO) NWs, are selected as the primary backbone and secondary branch NWs respectively. The highly localized and instantaneous temperature elevation by laser irradiation on the primary backbone metallic nanowire generates a nanoscale temperature fi eld followed by a photothermal reaction to selectively grow secondary branch nanowires along the backbone nanowire. An ultraviolet photo-sensor based on the proposed selective laser grew ZnO NW branch on an Ag NW backbone is further fabricated as the simplest form of proof-of-concept for all nanowire electronics and demonstrates its potential as future electronics with compact size, low power consumption and fast response. Scanning electron microscopy and numerical simulation were employed to analyze the general morphology of hierarchical heterogeneous nanowires and scrutinize the laser polarization eff ect of the laser utilized in this report on an Ag nanowire with its cross-section respectively. We expect that the proposed process can be further extended to other various material combinations whose hydrothermal growth routes are known. With a broader range of applicable nanowires, the proposed process shows great promise in the bottom-up fabrication of all-nanowire nanoelectronics, such as multifunctional environmental sensors.
Nu Si A Eom
Korea Institute for Rare Metal, Republic of Korea
Title: Synthesis and chariterization of 1-dimensional NdFeB nano fiber using electrospinning process
Biography:
Nu Si A Eom has completed PhD in the year 2017 at the age of 30 years from Hanyang University in Korea. Her master’s project was “Synthesis and Characterization of CdSe based Quantum Dots” and her PhD project was “New approaches for improving SnO2 and silicon-based semiconductor gas sensor at room temperature by micro/nano hybridization” in Korea. She has published several articles in SCI journal. Her main academic interests are quantum dot and semiconductor gas sensor. In 2018, Her current research concerns magnetic materials in Korea Institute for Rare Metal, Korea Institute of Industrial Technology.
Abstract:
The development of permanent magnet materials has led to the demand for innovative technologies such as electric motors and generators for energy conversion devices. Especially, The hard magnet materials based on NdFeB have been applied to wide areas such as automobiles, electrical devices and magnetic disks due to their excellent magnetic properties. The NdFeB including the transition metals such as Fe has also magnetoâ€optical eff ects. NdFeB based magnetic materials were generally synthesized using the classical powder metallurgy process. However, it was difficult to align easy magnetization axis (c-axis) and to obtain homogeneous microstructure for enhancing magnetic performances. Th ere has also been little signifi cant research on one-dimensional Nd-Fe-B magnetic synthesizing c-axis alignment. In this study, one-dimension NdFeB materials having c-axis alignment were facilely prepared through electrospinning process. In order to confirm magnetic properties with wire diameter, synthesis conditions were controlled by PVP volume. Th ese Nd-Fe-B fi bers had the diameter within a range from 700 to 1300nm. Th ese metal oxides polycrystalline fi bers were subsequently heat treated in the high vacuum furnace in the presence of the calcium as a reducing agent, resulted in Nd2Fe14B fi bers. Th e morphology of the synthesized Nd-Fe-B material was 1300nm analyzed by fi eld emission scanning electron microscope (FE-SEM) and X-ray diff raction (XRD). Th e magnetic property as a function of Nd-Fe-B wire diameter was conducted using vibrating sample magnetometer (VSM). Th e coercivity (Hci) of Nd2Fe14B fi bers was about 4800Oe. Th e values of saturation magnetization (Ms) and remanence (Mr) of fibers were 45emu/g and 20 emu/g.
Yi Zhu
Zhejiang University, China
Title: Influence of processing parameters on the energy consumption and mechanical properties of selective laser melted parts
Biography:
Yi Zhu has completed his PhD in the year 2013 at the age of 29 years from Royal Institute of Technology. He is an associate professor in the department of mechanical engineering at Zhejiang University. He has published more than 25 papers in reputed journals and has been serving as an associate editor of Journal of Tribology.
Abstract:
In selective laser melting (SLM), processing parameters are of a great importance which aff ects the amount of laser energy absorbed by metal powders. On one hand, the mechanical properties of the processed part depend on them. On the other hand, processing parameters also aff ect power profi le and scanning time, which directly relates to electrical energy consumption. In this research, we investigate the correlation between electrical energy consumption and mechanical properties and study whether electrical energy can be eff ectively reduced without signifi cantly compromising mechanical properties by optimizing processing parameters. 316L stainless steel was used as powder materials. Two key parameters, laser power and exposure time, were selected and several mechanical properties, including density, hardness, wear resistance, tensile strength, flexural strength and torsional strength, were tested. Th e results of electrical energy consumption and mechanical properties were jointly analyzed using growth rate comparison. It was found that the improvement of various mechanical properties with increased electrical energy consumption diff ers greatly. Density can be eff ectively increased without signifi cantly increasing the electrical energy, but the electrical energy needs to be greatly increased in order to achieve a high fl exural strength. Growth rate three-dimensional maps of mechanical properties and electrical energy consumption are presented as a reference for processing parameter optimization.