Prof. John Bowers, Epitaxial Growth of Quantum Dot Lasers on Silicon for Photonic Integrated Circuits
Institute for Energy Efficiency, University of California at Santa Barbara, , California, USA
Abstract: InAs quantum dot lasers epitaxially grown on Si show promise for achieving lower cost and higher performance photonic integrated circuits. The discrete density of states inherent to quantum dot lasers has many benefits: 1) reduced threshold current, 2) higher temperature operation, 3) reduced linewidth enhancement factor resulting in reduced reflection sensitivity and reduced linewidth, 4) improved reliability. Prospects and results for integration of quantum dot lasers with photonic integrated circuits will be discussed along with important applications of this technology.
Biography: John Bowers (F’94) is Director of the Institute for Energy Efficiency and a professor in the Departments of Electrical and Computer Engineering and Materials at the University of California, Santa Barbara. His research interests are primarily concerned with silicon photonics, optoelectronic devices, optical switching and transparent optical networks and quantum dot lasers. Bowers received the M.S. and Ph.D. degrees from Stanford University. He worked for AT&T Bell Laboratories and Honeywell before joining UCSB. Bowers is a fellow of the IEEE, OSA and the American Physical Society, and a recipient of the IEEE Photonics Award, OSA/IEEE Tyndall Award, the IEEE LEOS William Streifer Award and the South Coast Business and Technology Entrepreneur of the Year Award. He is a member of the National Academy of Engineering and the National Academy of Inventors.
Prof. Susumu Noda, Photonic Crystal Surface-Emitting Lasers for Paradigm Shift in LiDAR Sensing and Laser Processing
Department of Electronic Science and Engineering. Kyoto University, Japan
Abstract: LiDAR sensing and laser processing are becoming core technologies for smart mobility and smart processing. For example, LiDAR sensing is becoming essential for smart mobility of factory automation robots, farm machines, construction machines, and automobiles, while laser processing is becoming important for the smart processing of electronics, automobiles, and solar cells. Currently, key devices for these applications are broad-area semiconductor lasers, CO2 lasers and fiber lasers. However, these lasers have individual issues (or bottlenecks) such as low brightness (broad-area semiconductor lasers), large size and low efficiency (CO2 lasers and fiber lasers), and complicated configuration (fiber lasers).
In the present talk, I will show that the key to fix the above bottlenecks is the photonic-crystal surface-emitting lasers (PCSELs). PCSELs are an unprecedented type of semiconductor laser, with which single longitudinal and lateral mode oscillation can be achieved over areas as broad as millimeters in diameter. Their brightness, which is defined as power per unit area per unit solid angle, is expected to reach up to . In addition, PCSELs can achieve numerous functions, including the generation of beams with a variety of patterns and polarizations, and even electric two-dimensional beam scanning.
Following the above explanation of the fundamental properties of PCSELs, I will demonstrate the usefulness of PCSELs for LiDAR applications at first, then I will provide a perspective on their application to laser processing. I will also briefly mention that material systems for PCSELs are expanding to not only InGaAs/GaAs (900-1000nm), but also InGaAsP/InP (1.3-1.55um) and even InGaN/GaN (400-530nm). By doing so, I will show that PCSELs can serve as the key devices for various applications including LiDAR sensing and laser processing in the near future.
Biography: Susumu Noda is a full Professor, Department of Electronic Science and Engineering, Kyoto University, and also Director of Photonics and Electronics Science and Engineering Center, Kyoto University. His research interest includes physics and applications of photonic crystals and the related photonic nanostructures. He received various awards, including Optical Society of America Joseph Fraunhofer Award / Robert M. Burley Prize (2006), the IEEE Nanotechnology Pioneer Award (2009), Medal with Purple Ribbon (2014), the Japan Society of Applied Physics Outstanding Achievement Award (2015), and MOC Awards (2019).
Prof. Masataka Higashiwaki, Gallium Oxide: The Star of Hope for Compound Semiconductors?
National Institute of Information and Communications Technology, Japan
Abstract: Recently, gallium oxide (Ga2O3) has been getting much attention as a promising new compound semiconductor due to its excellent physical properties based on an extremely large bandgap of over 4.5 eV and the availability of large-size, high-quality, affordable single-crystal wafers produced from melt-grown bulk crystals. Much of the world-wide research and development has been motivated by the attractive material properties, and significant progress in all the aspects of Ga2O3 material and device technologies has been made over the past ten years. In fact, several milestones on the way to industrialization and commercialization of Ga2O3 power and RF devices have already been achieved. However, there is no room for doubt that the current device technologies are still immature, and that we still have a long way to introduce Ga2O3 transistors and diodes to practical markets.
In this talk, after an introduction of basic material properties of Ga2O3, I will provide a broad overview of the state-of-the-art Ga2O3 epitaxial growth and electronic device technologies. In addition, a brief outlook on Ga2O3 device applications will be given.
Biography: Masataka Higashiwaki received the B.S., M.S., and Ph.D. degrees in solid-state physics from Osaka University, Japan, in 1994, 1996, and 1998, respectively. After a two-year postdoctoral fellow, in 2000, he joined the Communications Research Laboratory (CRL), Japan. From 2007 to 2010, he took a temporary leave from the National Institute of Information and Communications Technology (NICT), which was renamed from CRL, and joined the Department of Electrical and Computer Engineering, University of California, Santa Barbara as a Project Scientist. He returned to NICT in 2010 and started a pioneering work on Ga2O3-based electronics. He is now a Director at Green ICT Device Advanced Development Center. Higashiwaki is a recipient of several awards, including the 2014 Japan Society for the Promotion of Science (JSPS) Prize and the 2007 International Symposium on Compound Semiconductors (ISCS) Young Scientist Award. His current research interest is in Ga2O3 device and material engineering.
Prof. Federico Capasso, Metasurfaces as heterogeneous nanostructured materials for multifunctional flat optics: from components to cameras
John A. Paulson School of Engineering and Applied Sciences Harvard University
Abstract: Metasurfaces are leading to the emergence of new optical components based on dispersion engineering of nanoscale structures, which enables circumventing the limitations of standard refractive and diffractive optics as well as the realization of new functions.1 Broadband achromatic optics based on metasurface and on hybrid refractive/diffractive design have potential for a wide range of scientific and industrial applications, from miniature spectrometers to ultracompact camera modules with greatly reduced footprint and ease of optical alignment. A new approach to polarization optics has also emerged based on a powerful generalization of Fourier optics.2 This has led to the demonstration of a compact, single shot, full Stokes polarization sensitive camera using a single metasurface, thus dramatically reducing the complexity of existing cameras and increasing their functionality.2 New depth sensors based on co-design of metaoptics hardware and software are also being developed, which require far less computational resources than stereo, and time of flight cameras. This convergence between optical design and AI is an emerging trend with far-reaching implications. Flat optics will have a major impact because it will use semiconductor fabrication technologies, such as DUV lithography, to mass produce optical component ad subsystem: chip makers will also become optical foundries.3,4 In this way it will take advantage of its inherent merits of better and easier aberration control, compactness and multifunctionality, compared to conventional optics.
- T. Chen, A. Y. Zhu, and F. Capasso Nature Reviews Materials 5, 604 (2020)
- A. Rubin et al. Science 365, 6448 (2019)
- Capasso Nanophotonics 7, 6953 (2018)
- S. Park, at al. Nano Letters 19, 8673 (2019)
Federico Capasso is the Robert Wallace Professor of Applied Physics at Harvard University, which he joined in 2003 after a 27 years career at Bell Labs from postdoc to Physical Research VP. His main accomplishments comprise bandgap engineering of heterostructure materials and devices, including the invention of the quantum cascade laser, metasurface based flat optics, MEMS based on the Casimir effect and the first measurement of the repulsive Casimir force. He is a member of the National Academy of Sciences, the National Academy of Engineering and the American Academy of Arts and Sciences. His awards include the Yves Medal of the Optical Society, the Balzan Prize for Applied Photonics, the King Faisal Prize, the American Physical Society Arthur Schawlow Prize, the IEEE Edison Medal and the Materials Research Society Medal.
Prof. Ursula Keller, Semiconductor disk lasers and SESAMs: material and design optimization
ETH Zurich(Swiss Federal Institute of Technology in Zurich), Switzerland
Abstract: We have observed a rapidly developing field of optically pumped vertical emitting semiconductor disk lasers (SDLs) such as VECSELs (Vertical External Cavity Surface Emitting Lasers) and MIXSELs (Modelocked Integrated eXternal-cavity Surface Emitting Lasers). The VECSELs have been successfully commercialized for power scaling at more unrestricted operation wavelength. In a VECSEL, the light is emitted perpendicular to the epitaxial layers, unlike edge-emitting lasers, where the beam propagates in the epitaxial layers. In contrast to a VCSEL (i.e. a Vertical Cavity Surface Emitting Laser), the external cavity of the VECSEL offers additional mode control for excellent transverse beam quality even at highest power levels and enables the integration of elements for nonlinear intracavity frequency conversion, wavelength tuning elements, passive modelocking with a semiconductor saturable absorber mirror (SESAM) and dual-comb generation. For the MIXSEL (Modelocked Integrated eXternal-cavity Surface Emitting Laser) the SESAM is integrated into the VECSEL layer stack. The MIXSEL then generates a modelocked pulse train from a simple linear straight cavity defined by the MIXSEL chip and the output coupler as the two end mirrors. The cavity length then adjusts the pulse repetition rate as demonstrated from 1 to 100 GHz with excellent noise performance. An additional intracavity birefringent plate enables dual-comb generation with an adjustable difference in the individual comb spacing. The performance of ultrafast SDLs has been constantly improved and this plenary talk will review the material and design optimization for shorter pulse durations, higher output powers from near infrared (IR) to mid-IR.
Biography: Ursula Keller has been a tenured professor of physics at ETH Zurich since 1993 (www.ulp.ethz.ch), and serves as a director of the Swiss research program NCCR MUST in ultrafast science since 2010 (www.nccr-must.ch). She received a „Diplom“ at ETH Zurich in 1984, a Ph.D. at Stanford University USA in 1989, was a Member of Technical Staff at Bell Labs USA 1989 to 1993. From 2014-2018 she has been a member of the research council of the Swiss National Science Foundation. She is the first elected president and co-founder of the ETH Women Professors Forum (https://eth-wpf.ch). She has been a co-founder and board member for Time-Bandwidth Products (acquired by JDSU in 2014) and for GigaTera (acquired by Time-Bandwidth in 2003). Her research interests are exploring and pushing the frontiers in ultrafast science and technology. Awards include the SPIE Gold Medal (2020), IEEE Edison Medal (2019), the European Inventor Award for lifetime achievement (2018), IEEE Photonics Award (2018), OSA Charles H. Townes Award (2015), LIA Arthur L. Schawlow Award (2013), ERC advanced grants (2012 and 2018), EPS Senior Prize (2011), OSA Fraunhofer/Burley Prize (2008), Leibinger Innovation Prize (2004), and Zeiss Research Award (1998).