Day 1 :
Keynote Forum
Manijeh Razeghi
Northwestern University, USA
Keynote: Recent advances of III-V semiconductor quantum devices from deep uv ( 200 nm) to thz (300 microns)
Time : 09:00-09:25
Biography:
Manijeh Razeghi joined Northwestern University, Evanston, IL, as a Walter P. Murphy Professor and Director of the Center for Quantum Devices in fall 1991, where she created the undergraduate and graduate program in solid-state engineering. She is one of the leading scientists in the field of semiconductor science and technology, pioneering in the development and implementation of major modern epitaxial techniques. Her current research interest is in nanoscale optoelectronic quantum devices. She has authored or coauthored more than 1000 papers, more than 30 book chapters, and 16 books. She holds 30 U.S. patents and has given more than 1000 invited and plenary talks. She received the IBM Europe Science and Technology Prize in 1987, the Achievement Award from the SWE in 1995, the R.F. Bunshah Award in 2004 and many best paper awards. Razeghi is an elected fellow of SWE (1995), SPIE (2000), IEC (2003), OSA (2004), APS (2004), IOP (2005), IEEE (2005) and MRS (2008).
Abstract:
Nature offers us different kinds of atoms. But it takes human intelligence to put different atoms together in an elegant way in order to realize manmade structures that is lacking in nature. This is especially true in III-V semiconductor material systems. Guided by highly accurate atomic band structure simulation, modern semiconductor optoelectronic devices are literally made atom by atom using advanced growth technology such as Molecular Beam Epitaxy (MBE) and Metal Organic Chemical Vapor Deposition (MOCVD). Recent breakthroughs have brought such quantum engineering to an unprecedented level, covering an extremely wide spectral range from 200 nm to 300 µm. On the short wavelength side of the electromagnetic spectrum, we have demonstrated III-nitride light emitting diode emitting in deep ultraviolet to visible. In the infrared, quantum cascade lasers (QCLs), and focal plane arrays (FPAs) based on quantum-dot (QD) or type-II superlattice (T2SL) are becoming the choice of technology in crucial applications such as environmental monitoring and space exploration. Last but not the least, on the far-infrared side of the electromagnetic spectrum, also known as the terahertz (THz) region, III-V semiconductor offers a unique solution of generating THz waves in a compact device at room temperature. Continuous effort is being devoted to all of the above mentioned areas with the intention to develop smart technologies that meets the current challenges in environment, health, security, and energy. In this talk, the latest advances in III-V semiconductor optoelectronic devices at the Center for Quantum Devices, Northwestern University, will be presented.
Keynote Forum
Anthony Krier
Lancaster University, UK
Keynote: Mid-infrared InSb quantum dot laser diodes
Time : 09:25-09:50
Biography:
Tony Krier is professor of physics at Lancaster University where he is director of the Quantum Technology Centre. He obtained his PhD in 1983 and joined Lancaster in 1989, where he founded the mid-infrared optoelectronics research group. He was promoted to Reader in 1999, then to Professor in 2003 and has published more than 190 papers. He has worked extensively on mid-infrared (2-5 μm) materials and devices and in 1996 he founded the international mid-infrared materials & devices conference (MIOMD). His recent work concerns antimonide nanostructures and dilute nitride alloys for use in mid-infrared lasers, photodetectors and solar cells.
Abstract:
The mid-infrared spectral range is technologically important for a variety of applications including gas sensing, optical spectroscopy, bio-medical diagnostics etc. Although InSb QDs have shown electroluminescence up to room temperature and are a promising candidate for diode lasers at wavelengths longer than 3 µm, there have been only a few reports of InSb QD lasers. In this work, we demonstrate coherent emission from InSb QDs at wavelengths between 3.02 µm and 3.11 µm at temperature, Tmax up to 120 K using pulsed excitation, with a threshold current density, Jth~1.6 kA cm-2 at 4 K. The gain and spectral tuning behaviour were also investigated. We developed a hybrid laser structure containing ten sheets of sub-monolayer InSb QDs in an InAs waveguide sandwiched between a p-InAs0.61Sb0.13P0.26 lower cladding layer grown by liquid phase epitaxy and an n+ -InAs plasmonic upper cladding layer grown by MBE. The laser peak blue shifts with increasing temperature when T<50 K. For T>50 K, the peak moves to longer wavelength as temperature increases. The modal gain of the laser was extracted from lasers with different cavity lengths resulting in a value of 29 cm-1, (or 2.9 cm-1 per InSb QD layer), which is close to that found in type II QW lasers emitting at similar wavelengths. The material gain was estimated to be 19 x104 cm-1, which is similar to that for type I QDs.
Keynote Forum
Michael A Fiddy
University of North Carolina at Charlotte, USA
Keynote: Managing light by scattering from structured materials
Time : 09:50-10:15
Biography:
Michael Fiddy received his Ph.D from the University of London, and was faculty member in Physics at Kings College London from 1979-1987. He moved to the University of Massachusetts Lowell in 1987 where he was ECE Department Head from 1994 until 2001. In January 2002 he was appointed the founding director of the Center for Optoelectronics and Optical Communications at UNC Charlotte and since 2011 has been site director for the NSF Industry/University Center for Metamaterials. He is a fellow of the OSA, IOP and SPIE and serves on the OSA Board of Directors.
Abstract:
Depending on material properties, size and shape, one can manage light-matter interactions, scattering phenomena and exploit resonant responses. More complex scattering units or metaatoms provide the opportunity to realize bulk materials with unusual electromagnetic properties. In this talk we investigate the role of local resonances and the effect of some degree of disorder of the meta-atoms on bulk material properties. Coupling between subwavelength elements can result in very large field enhancements and index values not predicted by an effective medium model. Similarly we describe some of the consequences of subwavelength periodicity of these elements and their role in defining bulk material properties. The consequences of disorder and coupling in metamaterial structures sets limits on the material response due to phase decoherence. One can draw parallels with the random phase approximation (RPA) which is routinely invoked in condensed matter physics. We have investigated the propagation of radiation through small numbers of meta-atoms or metamolecules, close to resonant frequencies, to determine how coupling and scattering affects their Q and bandwidth. From a scattering perspective, the coupling of local evanescent fields into propagating waves also contributes to these effective constitutive parameters in a subtle fashion determined by phase coherence. Depending on the materials employed from which the meta-atoms are fabricated, one can observe nonlinear responses. At microwave frequencies and using pulsed illumination, these structures show evidence of an energy exchange between neighboring (non-orthogonal) resonant modes, suggesting their use for tunable parametric applications as well. We discuss how these properties can be realized at optical frequencies.
Keynote Forum
John Michael Dallesasse
University of Illinois, USA
Keynote: The transistor-injected quantum cascade laser: A novel three-terminal device for Mid-IR wavelengths through THz frequencies
Time : 10:15-10:40
Biography:
Professor Dallesasse has over 20 years of experience in the Optoelectronics Industry, and has held a wide range of positions in technology development and management. Prior to joining the Department of Electrical and Computer Engineering at the University of Illinois in Urbana-Champaign, he was the Chief Technology Officer, Vice President, and co-founder of Skorpios Technologies, Inc., a company involved in the integration of compound semiconductor materials with silicon in a CMOS-compatible process. John’s research at the University is targeting photonic-electronic integration and novel coherent emitters for the mid-IR. His technical contributions include, with Nick Holonyak, Jr., the discovery of III V Oxidation, which has become an important process technology in the fabrication of high-speed VCSELs. John has over 60 publications and presentations, and 29 issued patents. He is a Fellow of the IEEE and OSA.
Abstract:
The quantum-cascade laser (QCL) has emerged as an important device for the generation of coherent light over operating bands from mid-IR wavelengths through THz frequencies. Wide-ranging applications in chemical detection and security have been enabled by the availability of these devices. At the same time, the device has certain limitations that are fundamental to its two-terminal nature and reliance on engineered quantum states that depend strongly on electric field, and as a consequence bias voltage. A promising enhancement to the QCL will be discussed that utilizes the transistor effect in a novel three-terminal n-p-n transistor structure to separate the field control from the current amplitude. This separation is achieved through placing the device cascade region in the reverse-biased base-collector junction of a heterojunction bipolar transistor (HBT), where the amplitude of the current flowing through the cascade region is controlled by the emitter-base bias. The ability to separately modulate the amplitude (emitter-base) and frequency (base-collector) creates unique opportunities for novel applications. The device design also allows a reduction of the doping level in and around the cascade region, which is ultimately expected to reduce free carrier absorption and improve wall-plug efficiency.
- Track 1: Advanced Science and Technology for Laser Systems
Chair
Anthony Krier
Lancaster University, UK
Co-Chair
Joachim Wagner Hans
Fraunhofer Institute for Applied Solid State Physics (IAF), Germany
Session Introduction
A. Krier
Lancaster University, UK
Title: Mid-infrared type II Insb quantum dot laser diodes
Biography:
Tony Krier is professor of physics at Lancaster University where he is director of the Quantum Technology Centre. He obtained his PhD in 1983 and joined Lancaster in 1989, where he founded the mid-infrared optoelectronics research group. He was promoted to Reader in 1999, then to Professor in 2003 and has published more than 190 papers. He has worked extensively on mid-infrared (2-5 μm) materials and devices and in 1996 he founded the international mid-infrared materials & devices conference (MIOMD). His recent work concerns antimonide nanostructures and dilute nitride alloys for use in mid-infrared lasers, photodetectors and solar cells.
Abstract:
The mid-infrared spectral range is technologically important for a variety of applications including gas sensing, optical spectroscopy, bio-medical diagnostics etc. Although type II InSb/InAs QDs have shown electroluminescence up to room temperature and are a promising candidate for diode lasers at wavelengths longer than 3 µm , there have been only a few reports of InSb QD lasers. In this work, we demonstrate coherent emission from InSb QDs at wavelengths between 3.02 µm and 3.11 µm at temperature, Tmax up to 120 K using pulsed excitation, with a threshold current density, Jth~1.6 kA cm-2 at 4 K. The gain and spectral tuning behaviour were also investigated.
We developed a hybrid laser structure containing ten sheets of sub-monolayer InSb QDs in an InAs waveguide sandwiched between a p-InAs0.61Sb0.13P0.26 lower cladding layer grown by liquid phase epitaxy and an n+ -InAs plasmonic upper cladding layer grown by MBE. Fig. 1 shows the laser peak blue shifts with increasing temperature when T<50 K. For T>50 K, the peak moves to longer wavelength as temperature increases. The modal gain of the laser was extracted from lasers with different cavity lengths resulting in a value of 29 cm-1, (or 2.9 cm-1 per InSb QD layer), which is close to that found in type II QW lasers emitting at similar wavelengths. The material gain was estimated to be 19 x104 cm-1, which is similar to that for type I QDs.
Gaetano Scamarcio
University of Bari, Italy
Title: Optical feedback interferometry in quantum cascade lasers
Time : 11:00-11:20
Biography:
Gaetano Scamarcio is full professor of Physics since 2002. He graduated in Physics in 1985 and received the PhD in Physics in 1989. From 1989 to 1990 he has been a research fellow at the Max-Planck-Institute für Festkörper-forschung, Stuttgart, Germany, and in 1992 a visiting scientist at the Walter-Schottky-Institute, Garching, Germany. In the period 1994-1996, in 2000 and 2001 he has been a visiting scientist of Bell Laboratories, Lucent Technologies (formerly AT&T), Murray Hill, NJ (U. S. A.). In 2006 he has been invited professor at the University of Paris 7.
His main research interests are in the fields of quantum cascade lasers, optical, vibrational and transport properties of semiconductor structures at the nanoscale, spectroscopic techniques for real-time monitoring of optoelectronic devices, optoelectronic sensors for mechatronics. His research activity is documented by 220 ISI publications, and 7 filed patents. His publications gathered more than 2200 citations with an ISI h-index of 26. He has given 50 invited presentations at international conferences and workshops. Awarded researches programs comprises contracts funded by European, UE, ESA, Italian, MIUR, MAP, CNR, INFM as well as regional agencies and industrial projects for an overal budget > 50 M euro.
Abstract:
After reviewing the features of self-mixing interferometry in quantum cascade lasers, its inherent ultra-stabilkity and its several metrological applications, I will present our recent results on a novel contact-free method based on the use of THz quantum cascade lasers operating under optical feedback to image in reflection mode the free electron plasma photogenerated onto a semiconductor surface. Self-mixing interferometry is also used to demonstrate the possibility to produce sub-wavelength patterns acting as metamaterials in semiconductors pumped by a spatially modulated near-infrared beam.
Philippe Christol
Univ. Montpellier, France
Title: Influence of the InAs/GaSb super lattice period composition on the electro-optical performances of T2SL infrared photodiode
Time : 11:20-11:40
Biography:
Philippe Christol is a professor in Electronic & Electrical Engineering and member of the Electronic Institute (IES) of Montpellier University, France, since 2005. He is specialist of infrared photodetection, in particular of antimonide-based photodetectors grown by Molecular Beam Epitaxy (MBE) on GaSb substrate. He is now Deputy Director of the IES laboratory (~180 members). He is author/co-author of over 80 publications in refereed journals, a book chapter and contributed to over one hundred communications in international conferences. His research interests currently focus on electrical and optical properties of new InAs/InAsSb and InAs/GaSb superlattice infrared photodiodes.
Abstract:
The last past years, Type-II super lattice (T2SL) made of InAs/GaSb nanostructures has emerged as a new material technology suitable for high performance infrared detectors. This was possible because T2SL is a particular quantum system with non-standard optical and electrical properties. Among T2SL specific properties, one of the main interesting is that several structures, with different InAs to GaSb thickness ratios in each SL period, can target the same cut-off wavelength. Recent previous work reports the study of photodiodes with different SL periods having the same cut-off wavelength at 5 µm at 77 K. This study shows the strong influence of the SL composition on dark current measurements, shape of spectral responses, quantum efficiency and type of background doping concentration of nid InAs/GaSb SL active zone. The objective of this communication is to use the flexibility of T2SL to fabricate by MBE a pin photodiode where the active zone is made of different SL periods. Influence of the SL period composition on the electrical and electro optical characterizations are reported and discussed. The results show that optimized SL structure for the MWIR domain can be designed by combining the best of each SL periods.
Joachim Wagner Hans
Fraunhofer Institute for Applied Solid State Physics (IAF), Germany
Title: Recent advances in widely tunable quantum cascade lasers and their use in spectroscopic sensing
Time : 11:40-12:00
Biography:
J Wagner received the PhD degree in Physics from the University in Stuttgart, Germany, in 1982. From 1982 to 1984 he worked at the Max Planck Institute for Solid State Research, Stuttgart, Germany, in the group of Prof. M Cardona before joining the Fraunhofer-Institute for Applied Solid State Physics, Freiburg, Germany, in 1985. There he is currently Deputy Director and Head of the Optoelectronics Department. He is also Professor at the Institute of Physics of the University of Freiburg and an associated member of the Materials Research Center Freiburg (FMF). His current research interests include III/V-semiconductor based optoelectronic devices in particular for the infrared spectral range, as well as their integration into modules and systems. He is author or coauthor of 460 scientific publications including several review papers and book chapters.
Abstract:
Widely tunable quantum cascade lasers (QCL) are ideal light sources for spectroscopic sensing exploiting characteristic finger print absorption of molecules in the mid-infrared (MIR) spectral range. Such broadband tunability can be achieved by placing a QCL chip with a broad gain spectrum into an external cavity (EC-QCL), using e.g. a diffractive grating as wavelength-dependent feedback-element. This way wavelength tuning over >25% of the central wavelength can be achieved routinely in the MIR spectral range. EC-QCLs deliver a well collimated low-divergence output beam with high spectral brightness, which enables a range of new applications. These include in-line MIR spectroscopic sensing of substances in aqueous solutions and MIR backscattering spectroscopy for stand-off detection of hazardous substances. First we report on recent advances in broadband-tunable MIR EC-QCL technology by presenting a first implementation of a rapid scan EC-QCL, employing a custom-made large diameter (=5 mm) MOEMS scanning grating in Littrow-configuration as wavelength-selective optical feedback-element. This way, a scanning rate of 1 kHz was achieved, which corresponds to 2000 full wavelength scans per second. Second, exemplary case studies of EC-QCL based MIR spectroscopy will be presented. These include in-line spectroscopy for the detection of contaminants in water as well as imaging MIR backscattering spectroscopy for the detection of residues of explosives and related precursors on various kinds of surfaces in a realistic environment.
Pascal Besnard
University of Rennes 1
France
Title: Coherency for a better detection
Time : 12:00-12:20
Biography:
Besnard Pascal has completed his PhD degree in Physics from University of Rennes and Postdoctoral studies at Ontario Lightwave and Laser Research Center, Toronto, ON, Canada. He is Professor at ENSSAT and was the Head of the Optronics department during 6 years and at the Head of the Laser Physics Group from 2000 to 2012. Since 2012 he is the Director of the unity CNRS Foton (optical Functions for the sciences of communication). His principal research interests include laser physics, noise, optical injection, optical feedback, and mode-locked lasers using semiconductor and fiber technology for optical communications and sensors.
Abstract:
Several scientific domains including defense, metrology, aerospace, and telecommunications require low frequency and intensity noise sources. Coherent lasers could improve detection and could offer new perspectives in the fields of instrumentation for high-speed optical telecommunications, microwave-photonics systems and highly sensitive sensors. If very coherent lasers have been realized in metrology or following fundamental studies (for examples, Menlo systems), their cost or complexity is prohibitive and there is a need for compact, low-cost coherent lasers (~Hz linewidth). We propose to use multi-stokes Brilouin lasers to reach such a goal (Hey Tow et al., “Towards more coherent laser sources by using a simple and compact Brillouin laser made of micro structured chalcogenide fiber” IEEE Photonics Technology Letters 25, 3, 2013). Generation of multiple Stokes orders with a single pump enables to filter out the pump noise as many times as the number of nonlinear components, which leads to a drastic reduction in the frequency noise, accompanied by a reduction in the intensity noise. We give for the first time frequency and intensity noise measurement for high-order Stokes components for Brillouin fiber lasers. We discuss future improvements and the impact of such low-cost, compact lasers.
Shien-Kuei Liaw
National Taiwan University of Sci. and Tech, Taiwan
Title: Linear-cavity fiber lasers investigation and application
Time : 12:20-12:40
Biography:
Shien-Kuei Liaw received the Ph.D. degree from National Chiao-Tung University, Taiwan, in 1999. In 1993, he joined the Telecommunication Laboratories, Ministry of Transportation and Communications, Taiwan. In 1996, he was a visiting researcher at Bellcore (now Telcordia), Red Bank, NJ. USA in 1996 and a visiting Professor at University of Oxford, UK in Autumn 2011. He is now a distinguished Professor and the Director of Optoelectronics Research Center of National Taiwan University of Science and Technology, Taiwan. He has authored and co-authored over 200 international journal articles and conference presentations. His research interests include optical communication, fiber devices and fiber sensing.
Abstract:
Recently, much more attention has been directed to diode-pumped single-longitudinal-mode (SLM) fiber lasers because of their high reliability, compactness, and capability of shot-noise-limited operation in the megahertz frequency range. In this paper, a SLM linear-cavity fiber laser at C-band wavelength is proposed and demonstrated by using only two subring cavities, either in serial or parallel connection. The employed saturable absorber filter and two subring cavities successfully suppress the multi-longitudinal-mode oscillation caused by spatial hole burning in a linear cavity. Tunable laser sources have seen various applications in recent years such as optical switching, network protection or digital communication. Among various tunable lasers, fiber lasers now compete directly in several domains with semiconductor lasers because they present the advantages of high brightness, low intensity noise, thermal stability, excellent coupling into a single mode fiber and better compatibility with fiber components. In this paper we develop an L band tunable erbium-doped fiber laser (TEDFL) using a broadband fiber mirror (BFM) and a tunable fiber Bragg grating (TFBG) as cavity ends. Several characteristics such as the gain fiber length, threshold pumping power, pumping efficiency and side-mode suppression ratio (SMSR) are studied. The wavelength tuning function is also demonstrated.
Anna Szerling
Institute of Electron Technology, Poland
Title: 16 mm InP-related quantum cascade laser
Time : 12:40-13:00
Biography:
Anna Szerling received the MSc in Physics from the Warsaw University of Technology, Warsaw, Poland, in 2002 and PhD degree in field of electronics from the Institute of Electron Technology, Warsaw, Poland, in 2008. Her main research interests include processing and characterization of the semiconductor devices. She currently works on the THz and MIR quantum cascade lasers. For 10.2014 – 11.2014, she joined the group of Prof. M. Razeghi at CQD, USA, as a Visiting Scholar.
Abstract:
The Quantum Cascade Laser are valuable as the sources for the detection of large organic hydrocarbon molecules like the BTX compounds in the 12–16 µm region or for radio-astronomy as local oscillators in heterodyne detectors. In this work, long wavelength 16 µm quantum cascade lasers will be demonstrated at room temperature with high peak output power using a bound-to-continuum structure design. The structure was grown by gas sources molecular beam epitaxy and consist of a 45 period active region embedded in an optical waveguide. The devices were processed in 50 - to 70 - µm wide mesa using wet chemical etching and a SiO2 for passivation. Multimode emission with pulsed peak power up to 700 mW at 30°C and above 200 mW at 100°C will be presented. The emission spectrum consists of modes around 641 cm-1 (λ~15.6 µm) and around 602 cm-1 (λ~16.6 µm).
Miriam S. Vitiello
NEST, CNR - Istituto Nanoscienze and Scuola Normale Superiore, Italy
Title: Photonic engineering and micro-cavity tuning of THz quantum cascade laser resonators
Time : 13:45-14:05
Biography:
Miriam Serena Vitiello received the Master degree in Physics (cum laude) in 2001 and the PhD Degree in Physics in 2006 from University of Bari. Since 2010 she is staff research scientist at the National Research Council in Italy, and she is leading the Terahertz photonics group at the Nanoscience Institute - NEST Laboratory and Scuola Normale Superiore in Pisa. She was visiting scientist for short research stages at the Technical University of Delft (April 2004, December 2004), at the Technische Universität of Munchen (July 2004) at THALES in Paris (2005) and at the University of Paris VII (2006). She coordinates the activities of Terahertz Photonics in the CNR Department of Physical Sciences and Technologies of Matter and she is a member of the scientific committee of more than 40 international conferences in the field of photonic devices. She is co-author of more than 100 refereed papers on international journals, holds 1 patent and delivered more than 60 invited talks at international conferences and more than 30 lectures at International Universities. She was the first European scientist to be awarded with the SPIE Early Career Achievement Award (2015). For her scientific research Miriam Vitiello has been granted the optoelectronics and photonics prize " Sergio Panizza " of the Italian Physical Society (2012), an International Scientific Author Award (USA, 2005) and two National Young Author Award (2004, 2005).
Abstract:
Terahertz (THz) radiation lies in the region of the electromagnetic spectrum, loosely defined as the 30-300 μm wavelength region that is often called “THz gap”. Recent technological innovation in photonics and nanotechnology is now enabling THz frequency research to be applied in an increasingly widespread range of applications, such as information and communications technology, sensing, medical diagnostics, global environmental monitoring, homeland security, and quality and process controls. Most of these applications require systems with targeted sensitivity and specificity exploiting advanced quantum devices, novel materials and technologies. To address the above application requirements, high power, widely tunable sources with controlled and directional beam profiles, together with high-speed and high-sensitivity resonant detectors need to be developed. This requires parallel developments in semiconductor materials and hetero structures, including micro/nano structuring and plasmonics, as well as related multifunctional THz optical components. The talk will provide an overview of our recent technological developments of Terahertz quantum cascade lasers, from the development of quasi-crystal THz intersubb and lasers, 1. To novel DFB concepts exploiting bi-period feedback gratings to control the emission frequency and the output beam direction independently. 2. A final emphasis on our micro cavity approaches for continuous tuning of THz QCL emission and waveguide adapters for efficient THz radiation out-coupling will be provided.
Mi-Yun Jeong
Gyeongsang National University, Korea
Title: In-situ study on optical properties and continuous laser tuning in cholesteric liquid crystal laser array
Time : 14:05-14:25
Biography:
Mi-Yun Jeong is an Associate Professor in the Department of Physics at Gyeongsang National University, Jinju, Korea. She received her BS degree from Gyeongsang National University, and her MS (2001) and PhD (2007) degrees from Korea University, under the guidance of Prof. D. G. Lim. Her current research interests include the second-order nonlinear optical effects of octupolar crystals, nanophotonics, plasmonics, and continuous tunable cholesteric liquid-crystal lasers. She has published 39 papers in peer-reviewed journals.
Abstract:
Cholesteric liquid crystals (CLCs) have become promising candidates for photonic crystal laser devices owing to their unique optical characteristics in mirror less lasing, as well as micron-sized thickness, low threshold, and lasing tunability in the full visible spectral range. In this paper, we introduced in-situ study on optical properties and continuous laser wavelength tuning in cholesteric liquid crystal laser array. General and polymerized CLC laser devices were fabricated to have fine-structured pitch gradient in a wedge CLC cell and to have tuning resolution less than 0.3 nm in abroad spectral range. The comprehensive optical properties of the laser lines and fluorescent spectrum generated by a CLC laser array were studied; the laser lines generated from a CLC with a right-(left-) handed circular helix were right-(left-) handed circular polarized, respectively. We found out that inside the photonic band gap, the CLC structure with right-(left-) handed helicity suppressed the fluorescence generated with right (left) circular polarized light, and instead the suppressed right (left) circular polarized light energy moved to the outside of the photonic band gap, so we can say that the fluorescence intensity outside of the photonic band gap is enhanced with right (left) handed circular polarized light. Depending on the position of the photonic band gap, the fluorescence quantum yield value increased by up to ~15%. And the polymerized CLC devices had good stability for a time of more than 1 year, and in response to strong external laser light sources, and thermal perturbation. And dynamic laser tuning by electric field and temperature control were also studied.
Stephan Sprengel
Technische Universitaet Muenchen, Germany
Title: Type-II quantum wells for InP-based surface and edge emitting lasers
Time : 14:25-14:35
Biography:
Stephan Sprengel was born in Erding, Germany, in 1987. He received the Dipl. Phys. degree from the Technische Universität München, Germany in 2012. Since then he has been working towards the Ph.D degree at the Walter Schottky Institut, Technische Universität München. Currently he is engaged in the research on InP and GaSb-based type-I and type-II quantum well lasers, LEDs and Photodiodes for the mid infra-red including design, epitaxial growth, manufacturing, and characterization. He is a member of the Deutsche Physikalische Gesellschaft, and the IEEE Photonics Society.
Abstract:
Lasers operating in the near- and mid-infrared have many applications - Medical sensing, surgeries, biosensing and contactless highly sensitive gas detection. In this range, InP-based edge emitting lasers and VCSELs using type-I Quantum Wells (QW) offer excellent performance up to 2.3 µm wavelength. Beyond this wavelength, edge emitting lasers based on GaSb demonstrate low thresholds up to 3.7 µm. For VCSELs as well as for III-V on silicon concepts, on the other hand, GaSb is not the material of choice, since the process as well as growth technology are not as far developed as for InP. In this talk we present an innovative concept for InP-based edge emitters and VCSELs for 2-3 µm, using type-II QWs. In the center, three type-II quantum wells are implemented. Each consists of a GaAsSb hole-confining QW surrounded by two GaInAsQWs for electron confinement, forming a W shaped band structure. These W-shaped QWs are separated by tensile strained GaAsSb. Additionally, the structure includes electron and hole blocking layers for electrical confinement. For optical confinement, wave guiding and cladding layers are surrounding the structure. We present lasers at 2.5 μm with threshold current densities of only 0.31 kAcm-2 extrapolated to infinite length corresponding, to 0.1kAcm-2 per QW. Furthermore laser at 2.7 µm are presented, operating up to 80°C in pulsed mode. Additionally, a concept for InP-based type-II VCSELs is discussed. First VCSEL results at 2.5 µm wavelength are very promising.
- Track 5: Advancements in Photonics
Chair
Dan Botez
University of Wisconsin, USA
Co-Chair
Weidong Chen
Université du Littoral Côte d’Opale, France
Session Introduction
Bruce Wessels
Northwestern University, USA
Title: BaTiO3 Photonic crystal electro-optic devices for 50 GHz applications
Time : 14:35-14:55
Biography:
Bruce Wessels is the W.P. Murphy Professor of Materials Science and Engineering, and Electrical Engineering and Computer Science at Northwestern University. He received his undergraduate degree from U. of Pennsylvania and PhD degree in Materials Science from MIT. He is a fellow of APS, OSA and ASMI. He is author/co-author of 360 articles on electronic, magnetic and optical properties materials and devices. He is the holder of 15 U.S. patents. He is a former president of TMS.
Abstract:
Due to an exponential increase of information processing and communications traffic requirements, there are needs for active devices for photonic integrated circuits that operate at 50 GHz and above. One way to increase the bandwidth of an EO modulator is to decrease its size. In this paper, we report the simulation, design, fabrication and characteristics of a millimeter scale, EO modulator operating in the V-band at a wavelength of 1550 nm based on BaTiO3 thin film platform. Using two-dimensional photonic crystal (PhC), decreasing its length and optimizing device design based on our recent simulations of EO and microwave characteristics 50 GHz devices were demonstrated. Integration of these active devices on silicon will also be discussed.
Dan Botez
University of Wisconsin, USA
Title: High-index-contrast photonic-crystal quantum cascade lasers: Watt-range coherent mid-infrared power sources
Time : 14:55-15:15
Biography:
D Botez is Philip Dunham Reed Professor at the University of Wisconsin-Madison. He received his PhD from University of California, Berkeley. He is co-inventor of the resonant-optical waveguide array concept which represents the first photonic-crystal laser structure for spatial-mode control. His recent work focused on mid-infrared quantum cascade lasers (QCLs), which led to the first model for carrier leakage in QCLs. He is a Fellow member of the IEEE and OSA, and recipient of the 2010 OSA Nick Holonyak Jr. Award. He has authored or co-authored more than 400 technical publicationsof which over 300 were refereed, and holds 52 patents.
Abstract:
Resonant leaky-wave coupling of antiguides has been used for phase-locking near-infrared (IR) lasers to high pulsed (10 W) and CW (1.6 W) near diffraction-limited (D.L.) powers. The structures are analogous to 2nd-order lateral distributed-feedback (DFB) structures; thus, they represent high-index-contrast (HC) (Δn ≈ 0.10) photonic-crystal (PC) structures that allow global coupling between array elements in an in-phase mode of uniform intensity profile. For mid-IR QCLs coherence over large apertures has been reported from PCDFB lasers and master-oscillator power-amplifier (MOPA) structures. PCDFBs involve diffraction gratings; thus, inherentlyhave low index contrast (Δn ~ 0.008) and have shown near-D.L. operation to only 0.5 W/facet pulsed power. Flared MOPAs, have shown near-D.L operation to 3.9 W, but have no index steps; thus, are vulnerable to thermal lensing in quasi-CW or CW operation. We have implemented resonant leaky-wave coupling in 8.4 μm-emitting arrays of QCLs. Preliminary results are 5.5 W near-D.L. peak powers. Such HC-PC structures hold potential for > 5 W quasi-CW coherent power in the 8-10 μm wavelength range, and > 5 W CW coherent power in the 4.5-5.5 μm wavelength range. Furthermore, in combination with single-lobe-emitting, 2nd-order metal/semiconductor gratings, such arrays hold potential for >15 W CW surface-emitted, coherent power from 2-D HC-PC mid-IR QCLs.
Weidong Chen
Université du Littoral Côte d’Opale, France
Title: Advanced photonic technologies for atmospheric measurements
Time : 15:15-15:35
Biography:
Weidong Chen is full Professor of Physics at the Université du Littoral Côte d’Opale (ULCO) in France. He received his PhD degree in 1991 from the Université des Sciences et Technologies de Lille (USTL) in France. Prior to joining the ULCO in 1993, he was an Assistant Professor at the USTL where he conducted research focusing on the development of laser sideband-based heterodyne THz spectrometer and its application to molecular rotation spectroscopy. His current research interests include developments and applications of photonic instrumentation (based on QCL, LED or optical parametric source) for optical metrology of atmospheric species: Trace gases (concentration, isotope ratios) and aerosols (optical properties). He has published more than 130 refereed technical papers and has co-authored over 140 presentations in the international conferences.
Abstract:
Chemically reactive atmospheric species play a crucial role in tropospheric processes that dominate regional air quality and global climate change. Contrary to long-lived species (such as greenhouse gases), real time in situ sensing of short-lived atmospheric molecules represents a real challenge due to their very high reactivity resulting in short lifetimes (of around 1-100 seconds) and ultra-low concentrations that measure in parts per billion by volume (PPBV) to parts per quadrillion by volume (ppqv). In this talk, we will overview our recent progress in the development of photonic instruments for in situ monitoring of such atmospheric species (like nitrous acid (HONO), nitrate radical (NO3), nitrogen dioxide (NO2). The experimental arrangements, based on the advanced photonic technologies (such as quantum cascade laser, light emitting diode) combined with selective and sensitive long optical path length enhanced absorption spectroscopy, as well as their applications to field observation and smog chamber study will be presented.
Giuseppe Leo
Univ. Paris Diderot, France
Title: Frequency doubling in AlGaAs microdisks at 1.55 µm
Time : 15:55-16:15
Biography:
Giuseppe Leo (born in 1966) received a Master in EE at “La Sapienza” University of Rome (Italy) and a PhD in Physics at the University of Orsay (France). From 1992 to 2004 he has been with the Rome-III University as assistant professor and then as associate professor. Since 2004 he has been full professor at the Paris Diderot University (France) and Head of the Nonlinear Devices group of MPQ Laboratory since 2006. His research domains include nonlinear optics and quantum optoelectronics, with a focus on AlGaAs platform. He has coordinated several research programs and published 80 articles, 9 book chapters and >150 conference papers. He has also edited 1 book and registered 3 patents. He is the director of the Denis Diderot School of Engineering.
Abstract:
Frequency conversion can be very efficient in whispering gallery mode semiconductor microresonators, thanks to high optical confinement and modal overlap. The crystallographic symmetry of AlGaAs, along with the circular geometry, provides effective quasi-phase matching without the burden of domain inversion. In this framework, some experimental studies have been recently reported on Second Harmonic Generation (SHG) in GaAs WGM microdisks. However, GaAs does not allow working with a Fundamental Frequency (FF) mode in the third fiber window of the telecom range, since the SH photon energy exceeds the energy gap and two-photon absorption losses are high up to 1800 nm.
Here we report on the demonstration of CW SHG in Al0.4Ga0.6As suspended microdisks on GaAs pedestal, with FF wavelength around 1.55 µm and an efficiency ï¨ = 0.7ï‚´10-3 W-1 comparable to state-of-the-art monolithic telecom devices. This result was obtained via the evanescent coupling between the disk and a tapered fiber, with 3.5 mW input power injected in the fiber.
Then we discuss the down-conversion that can occur in the same microdisk, with inverted roles for the SH (which becomes the input pump) and FF (which corresponds to the output signal and idler). In this case, with 3 ps pulses and a repetition rate of 300 kHz, a peak power of about 10 kW at 775 nm can provide signal and idler peak power of about 5 µW at degeneracy.
Finally, we illustrate the fabrication of the monolithic counterpart of such submicron-system, with a suspended AlGaAs nanowire in lieu of the fiber.
Jwo-Huei Jou
National Tsing Hua University, Taiwan
Title: Can OLED light-quality be good enough to justify lighting renaissance?
Time : 16:15-16:35
Biography:
Jwo-Huei Jou received his PhD in 1986 from University of Michigan, Ann Arbor, Michigan, USA, and worked as a Postdoctoral visiting scientist at IBM-Almaden Research Center, CA, USA, till 1988 before becoming a faculty in NTHU. He chaired the department from 2006 to 2009. He has published more than 120 journal papers and filed and/or been issued more than 60 patents, and has been serving as an editor of Fluorescent Materials and else.
Abstract:
Hydrocarbon-burning lighting measures, such as candles, oil lamps or torches, provide pleasantly warm-sensation, but are energy-wasting with problems like burning, carbon-blacking, flickering, oxygen consumption, and carbon-dioxide emission etc. Whilst, electricity-driven light sources, such as fluorescent tubes and LEDs, are energy-saving, but may cause blue hazards, including discoloring the paintings of van Gogh and Cezanne, irreparable damage to the retina of human eyes, and suppression of melatonin secretion etc. Notably, “Electric light at night may explain a portion of the breast cancer”, as reported by Stevens et al. in 2014. Undoubtedly, there is an urgent need for a blue-hazard free lighting source to safeguard human health. However, challenges arise for such a lighting source as high light-quality is desired while meeting the power-saving trend. Could one have an energy-saving, healthy lighting source with high light-quality to initiate lighting renaissance? To demonstrate such a possibility, we employ OLED technique with a high band-number of candlelight emission complementary emitters to fabricate a high quality, energy-saving and blue-hazard free OLED. The candle light emitting OLED can exhibit an approaching 90 color rendering index or an above 90 natural light spectrum resemblance index (SRI), with a power-efficiency at least 300 times that of candles at color-temperature below 2,000K. Most importantly, it shows a much lower melatonin suppression impact than candles, based on the same luminance level. It is indicated that the candle light-style OLED is physiologically-safer than candles, and the safest among all electricity-driven lighting sources ever.
Nasser Peyghambarian
University of Arizona, USA
Title: New ultrafast fiber lasers covering uv to mid-IR with nonlinear optics
Time : 16:35-16:55
Biography:
Nasser Peyghambarian received his Ph.D. in solid-state Physics from Indiana University in 1982. He then joined the University of Arizona where he is currently a Professor at the College of Optical Sciences and the Department of Materials Science & Engineering. He is an adjunct professor at the Electrical Engineering Department at UC San Diego, and the Director of the NSF Engineering Research Center for Integrated Access Networks. Additionally, he is the Chair of Photonics and Lasers at the University of Arizona and Director of the Photonics Initiative. He has over 500 publications in refereed journals and more than 25 patents.
Abstract:
Nonlinear optics (NLO) including second harmonic generation, fourth harmonic generation, optical parametric processes, difference frequency generation, and Raman effects would allow generation of new laser frequencies over a wide spectrum. Our recent results in developing fiber lasers sources covering uv to mid-IR will be summarized.
Angelo Angelini
Polytechnic of Turin, Italy
Title: Photon management assisted by surface waves on an all-dielectric platform
Time : 16:55-17:15
Biography:
Angelo Angelini has completed his PhD at the age of 28 years from Polytechnic of Turin. During his studies, he spent 6 months at Columbia University, Biomedical Engineering department. He is currently a research fellow at Polytechnic of Turin. He has published more than 10 papers in reputed journals.
Abstract:
An overview of recent results on photon management through surface modes on purely dielectric multilayers is provided. Diffraction as well as guidance and confinement of Bloch Surface Waves (BSW) are shown, and a particular focus on near-field coupling of emitters with BSW modes is provided. The ability of modifying the radiation pattern of emitters by employing nano structured surfaces is gaining growing attention in a variety of applications related to nanophotonics, such as few-molecule and quantum emitters detection. In this framework, Surface Plasmon Coupled Emission (SPCE) has demonstrated to be an effective way to address this issue. Generally, plasmonic-based mechanisms exploit a near-field transfer of energy from the emitters to plasmonic modes. However, the main drawback in using plasmons on metal is represented by ohmic losses, producing broad resonances and absorption of useful signal. An effect similar to SPCE occurs on properly tailored one dimensional photonic crystals sustaining BSWs. Due to the very low absorption coefficient of the 1DCP materials, the BSW-coupled fluorescence can propagate for longer distances as compared to plasmons. In addition, the use of dielectric structures offers interesting advantages such as a wide spectral tunability (from UV to IR); the possibility to have either TE or TM polarized BSW and higher Q-factors. By properly structuring the surface of 1DPC, light coupled to BSWs can be manipulated in several ways (e.g. diffracted, guided, and focused). In particular, spontaneous emission of emitters lying on the surface of 1DPC can be efficiently beamed out in arbitrary directions with low divergence.