Day 3 :
- Optoelectronics | Optical Communications and Networking
Location: Chattahoochee-B
Chair
Ishwara Bhat
Rensselaer Polytechnic Institute, USA
Co-Chair
Shiva Kumar
McMaster University, Canada
Session Introduction
Jun Hee Choi
Samsung Advanced Institute of Technology, South Korea
Title: On-glass/flexible GaN light-emitting diodes and blue light enhancement in CdS/ZnS quantum dots by surface plasmon resonance
Biography:
Jun Hee Choi received his PhD in Materials Science and Engineering from Seoul National University in 2012. He is currently a Research Master and Research Staff Member of the Device and System Research Center at Samsung Advanced Institute of Technology, Samsung Electronics. He has published more than 45 papers in SCI journals, more than 20 conference papers, and more than 50 US patents. His research includes GaN-based optoelectronics on unconventional substrates, and low dimensional electronics based on quantum dots, ZnO nanorods, and graphene.
Abstract:
There have been significant recent developments in the growth of single crystal gallium nitride (GaN) on unconventional templates for large-area blue or green light-emitting diodes (LEDs) which, together with layer transfer onto foreign substrates, can enable flexible and stretchable lighting applications. Here, the heteroepitaxial growth of GaN on amorphous and single-crystal substrates employing various interlayers and nucleation layers is discussed, as well as the use of weak interfaces for layer-transfer onto foreign substrates. Recent progress in low-temperature GaN-based red–green–blue (RGB) LEDs on glass substrates is discussed. Layer-transfer techniques with various interlayers are also discussed. These heteroepitaxial GaN growth and layer-transfer technologies are expected to lead to new lighting and display devices with high efficiency and full-color tunability, which are suitable for large-area, stretchable display and lighting applications. We shall also discuss blue light enhancement in CdS/ZnS quantum dots using surface plasmon resonance to achieve near-unity quantum yield.
Ishwara Bhat
Rensselaer Polytechnic Institute, USA
Title: Properties of hexagonal boron nitride grown on sapphire and silicon substrates for application in deep UV photonics
Biography:
Ishwara Bhat has received his PhD degree in Electrical Engineering from Rensselaer Polytechnic Institute in 1985 and has joined the Department as a Research Assistant Professor in 1988 and tenure tract Associate Professor in 1991. Since 1999, he has been a Full Professor. His research interests include narrow gap materials such as HgCdTe, InGaSb as well as high band gap materials such as SiC and hBN. He has over 30 years of experience working in II-VI, III-V and IV-IV compounds, and has demonstrated several growth and device innovations. He has published over 150 refereed journal articles and presented in over 100 conferences, both contributed and invited over the last 30 years.
Abstract:
Hexagonal boron nitride (hBN) is a wide bandgap semiconductor (Eg~6eV) with sp2-hybridized atomic sheets of boron and nitrogen. This material has attracted much attention for its properties such as high resistivity, high thermal conductivity (2000 Wm-1K-1), and stability in aggressive chemical environments and at high temperatures (up to 1000ºC). hBN, an insulating isomorph of graphene, has a small (1.7%) lattice mismatch to graphene and is expected to be atomically smooth and free from dangling bonds because of its sp2-hybridized bonding and weak interplanar Van der Waals bond. Hence, hBN is an excellent candidate to be used as a supporting substrate and gate dielectric for graphene based electronics. hBN is also an emerging material for deep UV photonics and for solid state thermal neutron detector application, since 10B, a constituent element of hBN, has a large thermal neutron capture cross section (3840 barns). This talk will present the recent results on the growth and characterization of thick (>12 μm) hexagonal boron nitride (hBN) and its use for deep UV detection and for solid-state thermal neutron detection. The hBN epilayers were grown by metalorganic chemical vapor deposition on sapphire and silicon substrates at a temperature of 1350ºC. A thin and amorphous nitride layer was formed at a low temperature (850ºC) on sapphire substrates, which enabled subsequent epitaxial hBN growth at 1350ºC. The influences of the sapphire nitridation temperature and the growth temperature on the film quality were analyzed by X-ray diffraction (XRD) measurements and UV response. X-ray diffraction peak from the (002) hBN plane at a 2θ angle of 26.7º exhibited the c-lattice constant of 6.66 Å for these films. A strong peak corresponding to the high frequency Raman active mode of hBN was found for the films at 1370.5 cm-1. X-ray photoelectron spectroscopy analysis confirmed the formation of stoichiometric hBN films with excellent uniformity. On silicon substrate, it was necessary to deposit first a thin film of boron to prevent silicon nitride formation and degradation of the film quality. Thickness up to 15 microns have been grown and characterized. These results will be presented at the talk.
Seth Bank
University of Texas, USA
Title: Digital alloy growth of AlInAsSb for low noise avalanche photodetectors
Biography:
Seth Bank has received his BS from University of Illinois at Urbana–Champaign. He has done his MS and PhD degrees from Stanford University. After a Post-doctorate at UCSB, he joined the University of Texas at Austin, where he is currently an Associate Professor of ECE and holds a Temple Foundation Endowed Faculty Fellowship. His research focuses on the growth and application of novel heterostructures and nanocomposites to electronic/photonic devices. He has co-authored over 200 papers and presentations and has received PECASE, NSF CAREER, AFOSR YIP, ONR YIP, DARPA YFA, Young Scientist Award from ISCS, Young Investigator Award from NAMBE, and several best paper awards.
Abstract:
The application of AlxIn1-xAsySb1-y to near- and mid-infrared optoelectronic devices has been hampered by the challenge of realizing high quality films, due to the wide miscibility gap. However, it was recently shown that AlInAsSb can be grown within the miscibility gap over a moderate range of compositions by molecular beam epitaxy using the digital alloy technique. We have extended this approach to realize AlInAsSb digital alloys covering the entire direct bandgap range that is lattice-matched to GaSb (Al fractions ranging from 0% to ~80%). The broadly-tunable bandgap (0.24 eV at 0% Al to 1.23 eV at 76% Al), along with the type-I band alignments of this lattice-matched quaternary make it attractive for advanced mid-infrared and near-infrared detectors and sources. For avalanche photodetectors in particular, these materials exhibit low excess noise characteristics – comparable to that of silicon and their band engineering flexibility proved indispensable for demonstrating the first low-noise separate absorption charge and multiplication (SACM) avalanche detector operating at telecom wavelengths and the first working staircase avalanche photodetectors. Here, we describe the growth and electrical/structural properties of these enabling materials.
Amur Margaryan
Yerevan Physics Institute, Armenia
Title: The radio frequency photomultiplier tube and optical frequency comb: High resolution, high rate and highly stable timing technique for single photons
Biography:
Amur Margaryan has completed his PhD from Yerevan Physics Institute and continued studies in the field of Experimental Nuclear Physics at Yerevan Physics Institute; Serpukhov proton accelerator, Serpukhov, Moscow region; JLab, Newport News, VA, USA; MAX-lab, Lund, Sweden; and GRAAL experiment at European Synchrotron Radiation Facility in Grenoble, France. He is the Leading Scientific Researcher at A I Alikhanyan National Science Laboratory (Yerevan Physics Institute). He has published more than 150 papers in reputed journals. His current research interest is in Ultrafast Photon Detectors and Optoelectronic Devices.
Abstract:
The radio frequency photomultiplier tube (RFPMT) combines the picosecond timing resolution of a streak camera with the fast readout of a photomultiplier. It is an entirely new device, currently under development at Yerevan and Glasgow in collaboration with Photek Limited (UK). Combination of the RFPMT with the optical frequency comb results in a high resolution (1 ps), high rate (≥ 1 MHz) and highly stable (10 fs/hr) timing technique for single photons. Such a device potentially has a large range of applications in fields ranging from physics to biomedical imaging. The principles of operation of the RFPMT will be described and possible applications to ultra-precise measurements in Physics and to ultra-high resolution optical microscopy will be outlined.
Min Jae Ko
Korea Institute of Science and Technology, Republic of Korea
Title: Light assisted low temperature sintering for the high-performance flexible dye-sensitized and perovskite solar cells
Biography:
Min Jae Ko is a Principal Research Scientist at Korea Institute of Science and Technology (KIST) and an KU-KIST Professor at Korea University. He obtained his BS (1995) and MS (1997) degrees from the Department of Fiber and Polymer Science and PhD (2001) from the Department of Materials Science and Engineering at Soul National University, Korea. He performed his Post-doc work at MIT from 2001 to 2004. Then he moved to Samsung Electronics Co., as a Senior Research Engineer in 2005. His research is focusing on the developments of materials and devices for the next generation flexible solar cells.
Abstract:
There have been significant progresses in the dye-sensitized (DSSCs) and perovskite solar cells (PSCs). Further cost reduction in high-speed manufacturing can be accomplished by continuous roll-to-roll printing processes using a flexible plastic substrate. Lightweight and flexible plastic solar cells can be installed even on non-flat surface, which makes them a possible ubiquitous power source for mobile electronics. The conventional TiO2 photo-electrodes of DSSCs and PSCs are prepaed via a high-temperature sintering at 500 °C after deposition of the TiO2 paste on fluorine-doped tin oxide (FTO) glass. However, the plastic substrates cannot withstand a sintering process at a temperature above 150 °C. This sintering process is essential since tight TiO2 inter-particle connections are required for better performance, resulting in the reduction of internal resistance and fast electron transport. Various low-temperature processes have been demonstrated such as chemical sintering, mechanical pressing, hydrothermal crystallization, electrophoretic deposition, microwave irradiation, ultraviolet (UV) light irradiation, near infrared (NIR) oven, and film transfer. However, most of these methods contain quite complicated multi-step processes, not proper for the rapid production of DSSCs and PSCs using the R2R process. We have developed several facile methods for the fabrication of efficient flexible solar cells on plastic substrates by using assisted sintering process. In this talk, several strategies to address these issues will be introduced.
Shiva Kumar
McMaster University, Canada
Title: Optical back propagation for mitigation of linear and nonlinear impairments in optical networks
Biography:
Shiva Kumar has completed his PhD degree (1997) from Osaka University, Japan. He has worked as a Post-doctoral Fellow at University of Jena, Germany, supported by Alexander von Humboldt Foundation from 1997-98. He has worked at Corning Incorporated, NY as a Senior Research Scientist (1998-2001). Currently, he is a Professor at McMaster University, Canada. He has published about 72 papers in many journals, authored a book on Fiber Optics, 7 book chapters, edited a book on Non-linear Fiber Optics, and holds 8 US patents.
Abstract:
An optical back propagation (OBP) technique is investigated to compensate for nonlinear impairments in point-to-point fiber optic communication systems as well as in networks with reconfigurable optical add-drop multiplexers (ROADMs). An OBP module consisting of an optical phase conjugator (OPC), amplifiers and dispersion-decreasing fibers (DDFs) fully compensates for the dispersion and nonlinear impairments of a transmission fiber. The dispersion profile of the DDF is calculated analytically by demanding that the OBP module compensates fully the nonlinear impairments due to the transmission fiber. The OBP module can be placed after each transmission fiber (inline OBP case) or at each network node (node OBP case). Although the digital back propagation can compensate for inter-channel nonlinear impairments in point-to-point systems, it would be impossible to mitigate these effects in digital domain in fiber optic networks since the channel path information is not available to the receiver. In contrast, OBP can compensate for inter-channel nonlinear effects in optical networks. Our simulation result shows that the OBP brings a significant performance advantage as compared to digital back propagation techniques in optical networks. In our simulations, non-ideal effects of the OBP module such as dispersion fluctuations of DDF, laser phase noise and relative intensity noise (RIN) of the laser used in OPC are included. We found that the node OBP outperforms the inline OBP since the noise introduced by the OPC in the case of inline OBP leads to performance degradations.
Avner Peleg
Afeka College of Engineering, Israel
Title: Stabilizing Raman crosstalk in massive WDM transmission networks by frequency dependent gain and loss
Biography:
Avner Peleg has received his PhD degree in Physics in 2001 from the Hebrew University of Jerusalem. He was a Post-doctoral Research Associate at Los Alamos National Laboratory and at the University of Arizona. He was an Assistant Professor at the University at Buffalo. He has published more than 30 papers in scientific journals and has been serving as an Editorial Board Member of the Heliyon journal.
Abstract:
Raman crosstalk is one of the major impairments in massive wavelength-division-multiplexing (WDM) optical fiber communication systems and an obstacle for achieving scalability in WDM fiber optics networks. In this work, we present a theoretical method for mitigation of Raman crosstalk by employing frequency dependent amplification, such that high-frequency communication channels are over-amplified, while low-frequency communication channels are under-amplified compared with mid-frequency channels. Our method is based on showing that the dynamics of optical pulse amplitudes in an N-channel transmission system can be approximately described by a relatively simple predator-prey model for N species. Numerical simulations with the full propagation model, consisting of a system of N coupled nonlinear Schrödinger equations, show stable long-distance propagation of the optical pulses in good agreement with the predictions of the simplified predator-prey model. Moreover, we theoretically demonstrated that transmission stability can be further enhanced in nonlinear waveguide couplers due to efficient mitigation of radiative sideband generation by the frequency dependent linear gain and loss.
- Nanophotonics and Biophotonics | Optical Physics | Surface Enhanced Spectroscopy
Location: Chattahoochee-B
Chair
P Boolchand
University of Cincinnati, USA
Co-Chair
Shu-Wei Huang
University of California, USA
Session Introduction
A Seteikin
Amur State University, Russia
Title: Numerical simulation of Raman scattering in biological tissues
Biography:
A Seteikin has studied Physics at the Pedagogical University in Blagoveshchensk. He has received his PhD in Physics in 2000. Currently, he is a Professor in the Department of Physics at the Amur State University in Blagoveshchensk. His scientific background is in the field of Laser - Tissue Interaction and Biophysics. In his work, he uses experimental and computational techniques. He has national and international collaborations in Physical and Life Science research.
Abstract:
The quantitative analysis of Raman spectroscopic signals in biological tissue is generally difficult. Typical samples contain a multitude of molecular species and, in addition, measurements altered by attenuation of the Raman signal. Realistic numerical modeling of the Raman process can help to facilitate the quantitative analysis of the Raman spectra, but approaches so far are scarce and often time-consuming. In this work, we report on two different and very efficient approaches for modeling of Raman scattering in turbid media irradiated by laser light. Both approaches utilize the Monte Carlo method to simulate the Raman scattering process. We compare the efficiency of both approaches and discuss possible future extensions and experimental validation. Most of simulations of Raman scattering use a two-step model, calculating the distribution of the incident radiation first and then re-launching Raman scattered photons based on this distribution. The reason for this approach is the fact that Raman scattering is a very weak process. Raman cross sections expected to be 10 orders of magnitude smaller than the quantum yields of fluorescence. The number of Raman photons or the weight of the Raman photon packages is extremely low after the Raman scattering event. The goal of this work is to provide a comparative evaluation of the two approaches for weaker processes such as conventional or resonance Raman scattering. In order to decide which model to use for a particular Raman application (normal, resonance, surface-enhanced, etc.), it is important to understand how these assumptions affect the numerical results obtained from the simulation.
A M Polubotko
Ioffe Institute, Russia
Title: Surface enhanced optical processes and regularities of their spectra in symmetrical molecules
Biography:
A M Polubotko has graduated from Physical Faculty of Leningrad State University in 1973. He has completed his PhD from Ioffe Institute, Russian Academy of Sciences and has been associated with the Azerbaijan Institute of Physics in Baku in 1983. Now he works as a Physicist Theorist and a Senior Scientific Researcher of Semiconductors and Dielectrics in the Department of Dielectrics and Semiconductors at Ioffe Physico-Technical Institute in Saint Petersburg. He has more than 120 scientific papers, preprints and abstracts published in reputed journals and reported on many Russian and International scientific conferences.
Abstract:
Surface enhanced optical processes SERS, SEHRS, SEIRA and single molecule SERS are of great interest. At present we have a reliable base in order to assert that their enhancement is associated with so-called strong quadrupole light-molecule interaction, arising in surface optical fields, arising near rough surfaces. The reason of appearance of these fields is a disordered medium where the characteristic size of the change of the electromagnetic field is equal to the characteristic length of the roughness. It appears that there is a strong enhancement of the electric fields and its derivatives in such a medium, especially near the places of substrate with a very large curvature. The second reason of the enhancement is an exclusive role of the quadrupole moments of the and type, which are of a constant sign that results in a strong increase of their matrix elements with respect to the ones of the dipole moments and quadrupole moments and , which are of a changeable sign. The increase of the number of moments, which are involved in the scattering results in appearance of forbidden lines in all the above processes. It appears and is confirmed experimentally that there are strong forbidden lines in symmetrical molecules with sufficiently high symmetry in SEIRA and SEHRS, which refer to the unit irreducible representation of the molecule symmetry group and the SERS lines, which refer to the vibrations with the irreducible representations describing transformational properties of the dipole moments. The last indicated lines are active in a usual IR absorption and are inactive in a usual Raman scattering. In addition the strong quadrupole light-molecule interaction experiences so-called electrodynamical forbiddance in molecules with cubic and icosahedral symmetry groups that results in the absence of the above mentioned lines in SERS, SEHRS and SEIRA spectra of molecules like methane, or fullerene . Analysis of experimental SERS and SEIRA spectra of strongly supports this result.
Dorota A Pawlak
Institute of Electronic Materials Technology, Poland
Title: Crystal growth-based methods used for manufacturing volumetric novel photonic materials as plasmonic nanomaterials and metamaterials
Biography:
D A Pawlak is a Professor at the Institute of Electronic Materials Technology (ITME) of Warsaw, and at the Centre of New Technologies (CeNT), University of Warsaw in Poland. She is currently the Head of the Department of Functional Materials at ITME and Leader of the Laboratory of Materials Technology at CeNT. Her research is linked to technology development for the manufacturing of new functional materials, such as plasmonic materials, metamaterials, materials with special electromagnetic properties and materials for solar energy conversion. She currently focuses on bottom-up methods such as directional solidification and crystallization, nanoparticles direct doping method and associated research.
Abstract:
We report on developments of fabricating nano and micro-structured volumetric plasmonic materials, metamaterials and other materials with unusual electromagnetic properties, utilizing crystal growth techniques based on directional solidification and crystallization. Two types of materials will be discussed: (i) based on directional solidification of eutectic composites, and (ii) directional solidification of dielectrics directly doped with functional nanoparticles of various size, shape and chemical composition (metallic-plasmonic, quantum dots) as well as various additional elements as rare earths, obtained by the nanoparticles direct doping (NPDD). It has been shown that with self-organization mechanism during the eutectic crystallization various shapes pertinent to metamaterials can be obtained as the 'split-ring resonator' geometry, rodlike or lamellar structures which can be used as hyperbolic metamaterials, or for subwavlength transmission of electromagnetic waves, eutectic-based tunable nanoplasmonic materials have been demonstrated for the first time, as well as enhanced second harmonic generation, strongly enhanced Faraday effect and others.
Amir Arbabi
California Institute of Technology, USA
Title: Flat and conformal optics with dielectric metasurfaces
Biography:
Amir Arbabi is currently a Senior Researcher at Caltech. From January 2017, he will be an Assistant Professor at the University of Massachusetts, Amherst. He received PhD degree in Electrical Engineering from University of Illinois at Urbana-Champaign. He has authored and coauthored over 70 papers in peer reviewed journals and conferences. His current research interests include photonic integrated circuits and on-chip integration of free space optical elements and systems.
Abstract:
Flat optical devices based on lithographically patterned sub-wavelength dielectric nano-structures provide precise control over optical wavefronts, and thus promise to revolutionize the field of free-space optics. Here, I have discussed our work on high contrast transmit-arrays and reflectarrays composed of silicon nano-posts located on top of low index substrates like silica glass or transparent polymers. Complete control of both phase and polarization is achieved at the level of single nano-post, which enables control of the optical wavefront with sub-wavelength spatial resolution. Using this nano-post platform, we demonstrate lenses, wave-plates, polarizers, arbitrary beam splitters and holograms. Devices that provide multiple functionalities, like simultaneous polarization beam splitting and focusing are implemented. By embedding the metasurfaces in flexible substrates, conformal optical devices that decouple the geometrical shape and optical function are shown. Multiple flat optical elements are integrated in optical systems such as planar retro-reflectors and Fourier lens systems with applications in ultra-compact imaging systems. Applications in microscopy and the prospects for tunable devices are discussed.
Michelle R Stem
Complete Consulting Services, LLC, USA
Title: A new paradigm: Metamaterial and upconversion effects in natural materials
Biography:
Michelle R Stem has a PhD in Materials Science Engineering, MBA in Management and BS in Chemistry. She has done her Post-doctoral Research and continued work as a Senior Materials Researcher at Complete Consulting Services, LLC. She applies interdisciplinary expertise through multi-scale analysis, computational modeling, and laboratory synthesis to study extremely rare inorganic, complex, and semi-conductor (ICS) materials. She researches ICS structural and property variations to discover and ultimately engineer new methods, applications, models, materials, and metamaterials with the goal of controlling photonic, optoelectronic, band gap and other properties. In addition to this, she also does research to develop materials that save energy (e.g. power differentials for photonic band gap versus electronic materials) and finds alternatives to using up rare resources.
Abstract:
This presentation will discuss the search, discovery, exploration and examination of the photonic control properties of natural, untreated opals having properties that were previously thought to exist only in artificially created materials. I will discuss the discovery of the first truly natural, untreated materials displaying: negative-index metamaterial, anti-Stokes upconversion, photonic glass, spontaneous laser emissions, and microspheroid cluster boundary effects. These materials display these photonic properties in visible light frequencies, with no toxic elements, in ambient conditions, and with significantly high energy conversion efficiency. Natural materials with such photonic control may be developed for broader applications in solar power, space exploration, energy production, stealth technologies, waveguides, microscopy, and photonic data storage/transmission.
Shu-Wei Huang
University of California, USA
Title: Chip-scale optical frequency combs: Advances in precision metrology
Biography:
Shu-Wei Huang is an Assistant Research Professor at the University of California, Los Angeles, with research interests in ultrafast lasers, nanophotonics, THz technologies, and nonlinear spectro-imaging. He has received his BS degree from National Taiwan University (2005) and his PhD degree from Massachusetts Institute of Technology (2012), both in Electrical Engineering. He was awarded the 2012 Jin-Au Kong Outstanding Doctoral Thesis Prize for breaking the single-cycle barrier in high-energy coherent light sources. In 2015, he received the Air Force Young Investigator Grant for his investigations in microresonator-based optical frequency comb. Currently, he serves as the Webinar Co-chair of OSA’s Nonlinear Optics Technical Group.
Abstract:
Optical frequency comb, a Nobel Prize awarded research, is a new time and frequency standard with unprecedented precision. It has been the cornerstone for breakthroughs in ultrastable time keeping, astrophysical spectrography, attosecond sciences, high-precision navigation, high-capacity coherent communication, and high-speed nonlinear spectro-imaging. Recently, continuous-wave pumped microresonators emerge as promising alternatives to the current benchmark femtosecond laser platform. These photonic frequency combs are unique in their compact footprints and offer the potential for monolithic electronic and feedback integration, thereby expanding the already remarkable applications of optical frequency combs. In this talk, I will present my recent work on photonic frequency combs. I will first report the generation of stable 74-fs optical pulses from a Si3N4 microring resonator via numerical modeling and analytic theory, the connection between the microresonator parameters and the ultrashort pulse qualities. I will also report a low-phase-noise photonic frequency comb with 18 GHz comb spacing, compatible with high-speed silicon optoelectronics. I will describe the strategy to fully stabilize the photonic frequency comb and achieve a chip-scale optical frequency synthesizer with a relative uncertainty of 2.7×10-16. Finally, I will cover the future endeavour towards chip-scale precision metrology.
Biography:
P Boolchand has received his PhD in Physics from Case Western Reserve University in 1969. He is a Professor of Electrical, Computer Engineering and Physics at University of Cincinnati. He has held Visiting Positions at Stanford University, University of Paris and Katholieke University of Leuven. He has co-authored over 275 journal publications. He is Fellow of the American Physical Society, and recipient of the Stanford Ovshinsky Award
Abstract:
Three topological phases of network glasses, flexible, intermediate and stressed-rigid are now widely recognized in chalcogenide and modified oxides. These are manifested as network connectivity is steadily increased in the 2 <
Renee Charriere
National Institute of Standards and Technology, USA
Title: Producing, characterizing and modeling nanostructured surfaces with complex visual
Biography:
Renee Charriere has completed her PhD in Optics and Quantum Mechanics in 2011 from the French Aerospace Lab (Office National d’Etudes et de Recherches Aérospatiales) and Paris VI University. As a Post-doctorate, she has worked on the optical characterization and modeling of nanostructured surfaces with complex visual appearance. She is now an Assistant Professor at the French Laboratory Georges Friedel in Saint-Etienne and is currently a Guest Researcher at National Institute of Standards and Technology in USA.
Abstract:
Gonio-apparent surfaces are characterized by huge variations of their visual rendering depending on illumination and observation directions. Such surfaces are more and more employed in industry for aesthetic reasons. Hotel Marqués de Riscal d’Elciego in Spain, for example, is covered by anodized titanium plates, which give the building a color change with sun position. The optical and colorimetric characterization of these materials is tricky as their optical properties vary highly with the illumination and/or observation geometries. Georges Friedel Laboratory has developed a high resolution optical device dedicated to the measurement of the bidirectional reflectance distribution function (BRDF) of such materials. This optical device has allowed the characterization of the color variations of gonioapparent materials such as anodized titanium and nanostructured anodized aluminum. Chromatic paths of the colors of the material as a function of illumination and observation direction have been deduced from the BRDF measurements. Electromagnetic models of the optical properties of these materials have been developed, showing good accordance with BRDF measurements. It has been for example demonstrated that it is possible to adapt the Fourier modal method, which is generally dedicated to the modelling of periodic nanostructures, to the partially ordered structure exhibited by nanostructured anodized aluminum.
Yukihiko Yamagata
Kyushu University, Japan
Title: Pulsed-laser Raman scattering for measurement of junction temperature of white-LED
Biography:
Yukihiko Yamagata has his expertise in Atomic and Molecular Physics, especially in Laser-aided Diagnostics. He has completed his PhD from Kyushu University, Japan. He is an Associate Professor and Leader of a Research Project focusing on standard measurement technology for solid state lighting devices in the Department of Engineering Sciences for Electronics and Materials, Kyushu University, Japan.
Abstract:
Recently, the characteristic of a light emitting diode (LED) has been improved dramatically, and the application to illumination is recognized as one of the most important issue to the manufacturers. It is well known that the efficiency, the output power, the life-time and the reliability of LED degrade with a temperature rise of the junction of LED. In order to fabricate a high quality LED module for illumination, it is necessary to keep the junction temperature low by improving the characteristic of LED chip itself, or by effective heat removal through a heat radiation design of the module. Therefore, it is strongly required to establish a standard method to measure the junction temperatures in LED module. Although several techniques, such as micro-Raman spectroscopy, infrared imaging, and temperature coefficient of diode-forward voltage are applied to estimate the junction temperature, there is no method that can simultaneously measure the junction temperature of the several chips located in a LED module, especially in a phosphor-deposited white-LED. Under these situations, we have been developing a pulsed-laser Raman scattering method for estimation of the junction temperature of LED, where the Raman shift of E2H mode of GaN layer is observed. This method has potentials of remoteness and simultaneous multipoint measurement, which lead to 2D mapping of the temperature of the LED module. This technique has been applied successfully to measure the junction temperature of phosphor-less blue-LED, and is considered to be one of the prospective candidates of temperature estimation method of white-LED. In this presentation, simultaneous observation of Raman spectra from several LED chips in a phosphor-less blue-LED module by a pulsed-laser Raman scattering method is demonstrated. Also, the influence of a phosphor deposited on the surface of blue-LED on Raman spectra will be discussed.
Ken-ichi Harada
Tohoku University, Japan
Title: Laser frequency locking with 46 GHz offset by using an electro-optic modulator for magneto-optical trapping of francium atoms
Biography:
Ken-ichi Harada has completed his PhD degree from Kumamoto University in Japan and joined the NTT Basic Research Laboratories. From 2010, he has been working at CYRIC, Tohoku University, as an Assistant Professor and then as a Lecturer. His research interests are in the fields of spectroscopy of atoms and molecules, laser cooling and trapping, fundamental symmetry violation studies, optical magnetometry, electro-optics devices and silicon photonic devices. He has published more than 33 papers in peer-reviewed journals.
Abstract:
The investigation of fundamental symmetry violations can elucidate the new physics beyond the standard model. Laser cooled and trapped Fr atoms have particular advantages for the precise symmetry violation measurements. Fr isotopes have ground state hyperfine splitting of about 46 GHz. For achieving laser cooling and trapping of Fr atoms, the hyperfine splitting frequency has to be accurately measured. The frequency difference of 46.1 GHz (210Fr) has to be bridged by two different lasers or has to be generated from a single laser by an electro-optic modulator (EOM). However, it is difficult to generate a frequency component with 46 GHz at the first sideband with an EOM in order to stabilize the frequency difference. In this work, we demonstrated the laser frequency locking with 46 GHz offsets between the trapping and re-pumping lights by generating a 10th order sideband using a fiber-based single-pass waveguide EOM. We successfully obtained the frequency locking error signal by performing delayed self-homodyne detection of the beat signal. Sweeping the trapped-light and re-pumping-light frequencies with keeping its frequency difference of 46 GHz was confirmed over 1 GHz by monitoring the Doppler absorption profile of iodine molecule. This technique enables us to search for a resonance frequency and magneto-optical trapping of Fr atoms. This can be applied for other radioactive as well as stable atoms with large hyperfine splitting.
Devki N Talwar
Indiana University of Pennsylvania, USA
Title: Optical properties of 3C–SiC/Si (001) defect microstructures by exploiting Raman scattering and X-ray absorption fine structure measurements
Biography:
Devki N Talwar, is a Distinguished University Professor in the Physics department at Indiana University of Pennsylvania (IUP), USA and conducts research on defects in semiconductor materials used in various electronics and optoelectronics applications. He has been with IUP for almost 29 years, and is the author of more than 130 refereed journal articles, four book chapters and more than 80 international conference presentations. He served as an Organizer in seven international conferences organized by Materials Research Society-USA, Singapore; 5th World Congress on Materials Science and Engineering-Spain, Optics, Mesoscopic Condensed Matter Physics, and Condensed Matter Physics-USA. He was invited as Honorary Guest member in Science Conclave with Nobel Laureates at IIIT-Allahabad from 2009-2014 and has delivered keynote addresses at Moscow Institute of Science and Technology and many other international conferences. His expertise in the sophisticated Green’s function technique is considered very useful for providing information on the electronic and vibrational properties of defects in semiconductors, quantum wells, and superlattices. He is recognized by the international community as a prolific researcher.
Abstract:
We report comprehensive studies of the optical and structural properties of microstructures in V-CVD grown 3C–SiC/Si (001) epifilms by exploiting Raman scattering and X-ray absorption fine structure measurements. By exploiting the phonon-assisted Raman scattering spectroscopy we have recognized the conventional optical modes ~794 cm-1, 973 cm-1 and two additional phonon features near ~ 625 cm-1 and 670 cm-1 - possibly falling between the forbidden gap of the acoustic and optical branches of 3C-SiC. Synchrotron radiation X-ray absorption fine-structure (SR-XAFS) measurements are performed by exploiting a double-crystal monochromator beamline at the National Synchrotron Radiation Research Center, Hsinchu, Taiwan. The measured X-ray absorption spectra are carefully examined to check the ability of experimental standards with the ab initio calculations. Temperature dependent profile of the unresolved ~670 cm-1 Raman band indicates disordering by defects and/or stress that makes phonon lifetime shorter to instigate mode broadening. Accurate assessments of lattice dynamical, thermal and defect properties are achieved by exploiting phonons from a rigid-ion model fitted to the inelastic X-ray scattering data and expending apposite group-theoretical selection rules. Lattice relaxations around Si/C atoms attained by first-principles bond-orbital model for isolated defects have helped evaluating the necessary force constant variations to construct perturbation matrices of “complex-defect-centers”. For the isolated intrinsic CSi and SiC defects (Td-symmetry) our methodical greens function (GF) theory predicted triply degenerate F2 gap modes near ~630 cm-1 and ~660 cm-1, respectively. The GF simulations of impurity vibrations for a neutral “anti-site” CSi-SiC pair (C3v-symmetry) provided gap-modes to appear within the broad ~670 cm-1 band at 664.8 cm-1 (a1) and 660.6 cm-1 (e). These outcomes implying possible links of ASP defect to a proto-typical DI center in 3C-SiC are compared and deliberated against the existing experimental data.
- Poster Presentations
Location: Chattahoochee-B
Chair
Karim D Mynbaev
ITMO University, Russia
Session Introduction
Young-Ho Seo
Kwangwoon University, South Korea
Title: A new chipset for generating computer-generated hologram
Biography:
Young-Ho Seo has received his MS and PhD degrees in 2000 and 2004, respectively from Department of Electronic Materials Engineering of Kwangwoon University in Seoul, Korea. He was a Researcher at Korea Electrotechnology Research Institute (KERI) in 2003 to 2004. He was a Research Professor of Department of Electronic and Information Engineering at Yuhan College in Buchon, Korea. He was an Assistant Professor of Department of Information and Communication Engineering at Hansung University in Seoul, Korea. He is a Full Professor of Ingenium College of Liberal Arts at Kwangwoon University in Seoul, Korea and a Director of Research Institute in DSI Tech Inc. Hi is now a Visiting Professor in University of Nebraska at Omaha, NE, USA. His research interests include realistic media, digital holography, SoC design and bus architecture.
Abstract:
Computer-generated holography is a method of digitally generating interference fringe patterns. Recently, the term of “computer-generated holography” has been used to present the whole process of preparing holographic light wavefronts suitable for various displaying. The resultant images generated by the computer-generated holography are called computer-generated hologram (CGH). In case of generating synthetic holograms, the CGHs have the advantage that the objects don’t need to possess any physical reality at all. In case of optically generating a hologram from existing objects, if it is digitally recorded and processed or displayed, this is corresponding to the CGH as well. Wavefront calculations for the CGHs are computationally very intensive. Although the researchers use modern mathematical techniques and high-performance computing equipment, real-time operation is very difficult according to the amount of the object points. There are many various methods for calculating the interference pattern for a CGH. Among them, we use the point source method. In this paper, we propose a new hardware architecture to generate CGHs based on the block based calculation method and implement a VLSI (very large scaled integrated circuit) in ASIC (application specific integrated circuit) environment. The proposed hardware has a structure that can produce a part of a hologram in the unit of a 12x12 block in parallel. After calculating a block of a hologram by using an object point, the calculation is repeated to all object points and intermediate results from them are accumulated to produce a final block of a hologram. Through this structure, we can make various sizes of holograms with the optimized memory access in real-time operation. The proposed hardware was implemented in the Hynix 0.18 um CMOS technology of MagnaChip Inc., and has 876,608 gate counts. It can generate complex holograms unlike the previous researches and stably operate in the clock frequency of 200 MHz.
I Filikhin
North Carolina Central University, USA
Title: Electron localizations in binary InAs/GaAs quantum systems and their optical detection
Biography:
I Filikhin is a Research Professor in the Department of Physics at North Carolina Central University. He received his Doctorate in Theoretical Physics from St. Petersburg State University in Russia (1993). His research includes nuclear low-energy physics, hyperphysics, nano-science and semiconductors physics, as well as computational physics. He is author/coauthor of more than 90 scientific papers. His current researches are related to the effective potential approach for electron structures in complexes of the quantum dots and rings, cluster models for light nuclei and hypernuclei.
Abstract:
We studied the electron localization and spectral distributions of electron localized/delocalized states in binary InAs/GaAs quantum complexes. Such weakly coupled binary systems demonstrated perspectives for nano-sensor applications. Electron tunneling in double quantum dots (DQDs) and quantum wells (DQWs) was studied with dependence on distance between QDs. We showed that the tunneling between identical QDs in DQD goes consecutively from the higher energy levels to the ground state when the inter-dot distance is decreased. The case of non-identical QDs in DQD has an essential difference and the relation between these two cases is discussed. Generally, the violation of symmetry of the DQD geometry reduces tunneling. In particular, we found that electron tunneling is extremely sensitive on shape symmetry violations in binary systems, which can be potentially used for nano-sensing. To investigate the method of detection of the localized/delocalized states change we considered the electron tunneling in InAs/GaAs dot-well complex. Modeling of carrier transfer from the barrier in InAs/GaAs dot-well tunnel-injection structures was performed. A relation between the experiment and our calculations will be presented and perspectives to use the method for nano-sensor applications will be discussed.
Goran Rasic
North Carolina Central University, USA
Title: Inexpensive method for wafer size laser scribing of arbitrary patterns
Biography:
Goran Rasic has received his PhD in 2014 from NC State University and is currently a NSF Post-doctoral Fellow at NC Central University. His research interests include nanoscale lithography, novel manufacturing techniques and magnetic and multiferroic thin films for device applications. He has published 8 papers, one book chapter and two patents.
Abstract:
Micro- and nanolithography techniques are a key factor in pushing the limits of science and technology. This is especially true in the semiconductor industry which has made remarkable progress over the last 20 years. With the technology focus moving to smaller and smaller scale, numerous lithography methods of manufacturing complex micro- and nanostructures (such as photo, nanoimprint, e-beam, soft and focused ion beam) have been developed. However, most of these techniques have limitations in the form of material choices, speed, cost and/or pattern shape/size. Clearly a fast, low-cost and versatile method of producing high quality surface patterns is needed. Here, an approach that offers low-cost, fast manufacturing of complex patterns over large scale is presented. The method proposed can be used to directly describe the desired pattern on the light sensitive material or create a master to be used for transferring a pattern to the appropriate material. The desired motif is drawn on a computer and transferred to the photoresist using our setup consisting of commercially available LED laser. Surface of the material can then be engraved with the predetermined pattern using standard etching techniques. The method described here represents an affordable, fast and versatile way of manufacturing complex micro- and nanostructures without some of the design, throughput and material limitations faced by costlier techniques, making state of the art research more affordable and accessible.
- VIdeo Presentation
Location: Chattahoochee-B
Session Introduction
Peng-Sheng Wei
National Sun Yat-Sen University, Taiwan (ROC)
Title: Incapability of laser drilling affected by interfacial transport processes across the induced keyhole
Biography:
Peng-Sheng Wei has received his PhD in Mechanical Engineering department from University of California, in 1984. He was a Professor in the Department of Mechanical and Electro-mechanical Engineering of National Sun Yat-Sen University, Kaohsiung, Taiwan, since 1989. He has contributed to the understanding and applications of electron and laser beam, plasma, and resistance welding through theoretical analyses coupled with verification experiments. He has published more than 80 journal papers and has given keynote or invited speeches in international conferences more than 70 times. He is a Fellow of AWS (2007), and a Fellow of ASME (2000). He also received the Outstanding Research Achievement Awards from both the National Science Council (2004), and NSYSU (1991, 2001 and 2004), the Outstanding Scholar Research Project Winner Award from National Science Council (2008), the Adams Memorial Membership Award from AWS (2008), the Warren F Savage Memorial Award from AWS (2012), and the William Irrgang Memorial Award from AWS (2014). He has been the Xi-Wan Chair Professor of NSYSU since 2009, and is an Invited Distinguished Professor in the Beijing University of Technology, China (2015-2017).
Abstract:
This study theoretically identifies the factors affecting the keyhole collapse during drilling with a high power density laser beam. Laser drilling is widely used in various manufacturing technologies. This work studies quasi-steady one-dimensional compressible flow behavior of the two-phase vapor-liquid dispersion in a vertical keyhole of varying cross-section, paying particular attention to the transition between the annular and slug flows. The results find that the effects of transport processes across the induced keyhole wall affected by surface tension, friction force, and liquid entrainments on incapability of drilling. The predicted results agree with physical intuition and exact closed-form solutions in the absence of friction and energy absorption. Controlling the factors to enhance efficiency and quality of drilling is therefore provided in this work.