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Friday March 24th, 12:00 pm in Henley Hall 1010 New machine learning algorithms such as deep neural networks and the availability of large datasets have created a large drive towards new types of hardware capable of executing these algorithms with higher energy-efficiency. Recently, silicon photonics has emerged as a promising hardware platform for neuromorphic computing due to its inherent capability to process linear and non-linear operations and transmit a high bandwidth of data in parallel. At Hewlett Packard Labs, an energy-efficient dense-wavelength division multiplexing (DWDM) silicon photonics platform has been developed as the underlying foundation for innovative neuromorphic computing architectures. The latest research on our silicon photonic neuromorphic platform will be presented and discussed.  From An Energy-Efficient and Bandwidth-Scalable DWDM Heterogeneous Silicon Photonics Integration Platform -- https://doi.org/10.1109/JSTQE.2022.3181939 Biography:
Bassem Tossoun received his PhD in Electrical Engineering at the University of Virginia in 2019 with his research interests including silicon photonics and the design, fabrication, and characterization of optoelectronic devices for data communications. Currently, he is a Senior Research Scientist at Hewlett Packard Labs working on heterogeneously integrated III-V on silicon photonic devices for next-generation optical computing and communications.  Friday, Mar 3rd, 1:00 pm (PST) in-person in Henley 1010 Abstract: The insatiable growth of datacenter traffic mandates increasing the capacity of cost-effective transceiver technologies to meet the foreseen demand. Competing configurations include IM/DD and coherent transceiver architectures. In this presentation we will discuss the challenges and opportunities associated with these two options including such topics as: wavelength, reach modulation format, modulator technology, and power consumption. Bio: David V. Plant has been a Professor in the Department of Electrical and Computer Engineering at McGill University, Montreal, Canada, since 1993 where he currently holds a Tier I Canada Research Chair in Optical Fiber Communications Systems. He received his Ph.D. from Brown University, and he was at UCLA as a Post-Doc before joining McGill University. He was a Killam Research Fellow and Received the IEEE Photonics Society Engineering Achievement Award. He is a fellow of Optica, EIC, CAE, IEEE, and the RSC. 
February 23, 2023 at 9:00 am in Henley Hall 1010 and on Zoom  Schematic diagram of optical waveguides with multiple longitudinal discontinuities (i − 1) [12]. The first discontinuity is located at z = 0. {ψ −}i and {ψ +}i are the backward and forward propagating fields, respectively, usually used in BiBPMs. Afaf Said, Khaled S. R. Atia, and S. S. A. Obayya, "On modeling of plasmonic devices: overview," J. Opt. Soc. Am. B 37, A163-A174 (2020) Nanophotonics modelling for 21st century applications is becoming vital. The computational modeling provides a fundamental understanding of the relying physics behind the operation of photonic devices. However, computational modeling is still a challenge as some of the existing modeling techniques fail to capture the correct behavior of nano-photonic devices. In this regard, this talk will introduce an overview of the existing computational modeling tools for analyzing photonic devices, in general, and highlighting their salient features and shortcomings. It is well known that “plasmonics” plays a vital role now in localising the optical field beyond the diffraction limit and hence in integrated optics. Therefore, the talk will focus on plasmonics modeling issues and the failure of the classical electromagnetic solvers to accurately characterize the nano-plasmonic devices. Therefore, new accurate and stable beam propagation method will be introduced for analyzing plasmonics in the classical regime. The rigor of this approach is mainly because of relying on the finite elements method and the twice faster Blocked Schur algorithm which can exactly represent all the wide spectrum of radiation, evanescent, and surface modes produced by the strong discontinuity between metal and its surroundings. Moreover, in merging quantum plasmonic devices, it becomes essential to introduce “Quantum Corrected Model (QCM)” in order to accurately model these devices, and the basics of QCM will be also discussed. Dr. Salah Obayya Biography: Salah S A Obayya joined Zewail City of Science and Technology (ZC) in 2012 where he is now Chair Professor and Founding Director of Center for Photonics and Smart Materials (CPSM). He occupied the positions of the Vice Chairman of ZC and Director-General of Research Institutes at the same institution. Prior to Zewail City, he took up several academic posts at Brunel University UK (tenured Associate Professor, 2002), University of Leeds, UK (tenured Professor, 2006) and University of South Wales, UK (tenured Chair Professor, 2008) where he was the Founding Director of Photonics and Broadband Communications (PBC) Research Center and also he was the Director of Postgraduate Programs at the same institution. In May 2006, he has been naturalized as “British” citizen.
He has established an outstanding international reputation in the area of green nanophotonics with focus on the intelligent computational modeling of modern nano-photonic devices enabling technologies needed to realise low-carbon green society. He has published 271 journal publications, mostly in OSA, IEEE and IET/IEE, authored 3 books (Computational Photonics, Wiley 2010 and Computational Liquid Crystal Photonics, Wiley 2016, Computational of Photonic sensors, 2018) both are adopted references for Graduate Programs in Photonics at international Universities such as MIT, Purdue University, Indian Institute of Technology, National University of Singapore, Mansoura University and Zewail City, and 264 conference papers in international conference in photonics, many of these are invited talks, and keynote lectures, attracted external funding, from both industry and Research Councils, in the region of $ 4M, and supervised to successful completion 35 PhD students, over 70 MSc/MRes/MPhil students and 15 postdoctoral research fellows. He led the team that developed one of the world’s best comprehensive numerical packages for the analysis, design and optimization of nano-photonic devices, and subsystems, where a number of “world-first” numerical approaches have been developed. His five key papers introducing his novel numerical package; have been cited more than 400 times. His publications also have been cited more than 4000 times, with an h-index of 34 and i10-index of 118. His numerical package has been widely adopted by both academic and industrial Photonics communities to analyze, design and optimize the performance of a wide range of nano-photonic devices employed for applications in solar cells, optical telecoms, sensing, optical imaging and encryption and other applications. He has served the International Photonics Society through active contribution to the organization and technical committees of a number of international conferences. Since 2007, he has been an Associate Editor-in-Chief of the IEEE Photonics Technology Letters, and Associate Editor-in-Chief of the Journal of Optical and Quantum Electronics, and served as Guest Editor-in-Chief of J Optical and Quantum Electronics (2010), and founding member of Editorial Board of Materials Theory Journal (Springer) and acted as Reviewer for many international Photonics Journals such as IEEE J Lightwave Technology, IEEE Photonics Journal IEEE J Quantum Electronics, IEEE J Selected Topics in Quantum Electronics, IET Optoelectronics, OSA Optics Express, OSA Optics Letters, and many others. Moreover, he acted as Technical expert and Reviewer for a number of research funding councils and learnt societies such as Engineering and Physical Sciences Research Council (EPSRC), UK, Royal Society, UK, Royal Academy of Engineering, UK, National Academy of Arts and Sciences, Holland, Science and Technology Development Fund, Egypt, National Telecom Regulatory Authority (NTRA), Egypt and others. 
Friday, Jan 27, 1:00 pm (PST) in-person in Henley 1010  From Ref [4]: Spatial patterns in a monolithic ring laser comb. (a) Schematic of a ring cavity laser. (b) Intensity spectra of a ring QCL. Bloch gain leads to a multimode instability through phase turbulence [25]. A sech 2 envelope is fitted to the spectrum. Elimination of Bloch gain yields single-mode operation. (c) Temporal evolution of the intensity shows an initial turbulent regime that forms a frequency comb after 510 000 round trips. Optical frequency combs (OFCs) – whose spectra consist of a large number of equidistant modes – stand as the cornerstone of modern optics with applications ranging from fundamental science to sensing and spectroscopy. In this pursuit, semiconductor lasers have recently gained vast attention as an electrically-driven platform for self-starting OFCs, without the need for any additional components that are necessary for standard mode-locked lasers. Here, we explain the multitude of mechanisms that arise from fast gain dynamics of these lasers leading to rich nonlinear behavior. We first concentrate on the free-running combs in Fabry-Perot resonators, which are characterized by a linear frequency chirp and a continuous-wave intensity. We reveal the conditions for the formation of these frequency-modulated (FM) combs along with the optimization techniques that increase their spectral bandwidth [1,2]. Alternatively, ring resonators support unidirectional fields, where the multimode regime occurs only in the presence of the parametric gain, allowing the sidebands to overcome the lasing threshold [3]. We show that sensitive interplay between the dispersion and resonant Kerr nonlinearity [4] leads to the emission of OFCs and the formation of localized patterns in the laser output – ultimately enabling soliton generation. [1] N. Opačak, et al., Phys. Rev. Lett. 123, 243902 (2019). [2] M. Beiser, et al., Opt. Lett. 46, 3416 (2021). [3] M. Piccardo, et al., Nature 582, 360 (2020). [4] N. Opačak, et al., Phys. Rev. Lett. 127, 093902 (2021). Nikola Opačak obtained his PhD at the Technical University of Vienna in 2022, in the group of Prof. Benedikt Schwarz. His work focuses on semiconductor lasers, nonlinear dynamics, optical frequency combs, and band structure and carrier transport modeling. Nikola is currently a PostDoc at the Technical University of Vienna at the Institute of Solid State Electronics, and a research associate in the Capasso Group at Harvard University. 
Friday November 4th at 1:00 pm in ESB 2001 Coherent optical technologies enable high-bandwidth communication across the globe and are fundamental to the fiber optic backbone of the internet. Due to exponential increase in demand for bandwidth, and the subsequent rise of hyperscale data centers, coherent systems are now being used for shorter links, such as between data centers, or even inside of them. In this talk, I will first briefly review trends and the evolution of coherent optical modems, highlighting Ciena’s technology and contributions. I will discuss various challenges and solutions for next-generation coherent modems used in traditional medium-haul and long-haul links. In the second part of the talk, I will discuss the transition of coherent technologies to inter- and intra-data center optical links, focusing on data center switching bottlenecks, such as frontplate density, rack power consumption, and PIC shoreline density. I’ll then briefly review the use of optical frequency combs as a potential enabling technology for future data center links. In the final part of the talk, I’ll shift gears to professional development and give a brief overview of my experience with the Stanford Optical Society, balancing priorities during grad school, and the transition to industry. Brandon Buscaino received a Ph.D. in Electrical Engineering from Stanford University in 2020 as a member of Prof. Joseph M. Kahn’s Optical Communications Group. While there, he developed novel techniques for electro-optic frequency comb generation and designed coherent optical links for next-generation co-packaged data center communications using external and integrated light sources. As president of the Stanford Optical Society, the graduate student Optica chapter, he organized community conferences, led outreach presentations at FiO+LS, and served on the Optica Student Leadership Conference planning committee. Since then, he has continued professional involvement in optics by participating in various Optica technical groups and committees as well as several Congressional Visits Days, advocating for optics and photonics funding in Congress. Since 2020, Brandon has worked predominantly with coherent optical communications technologies, such as digital coherent optical systems up to 800 Gb/s per wavelength and point-to-multipoint coherent pluggables. Currently, he is a Research Scientist at Ciena Corporation, focusing on novel applications of next-generation coherent optical communications systems and subsystems. Brandon has co-authored over a dozen journal and conference papers as well as several patents and is an active reviewer for J. of Lightwave Tech., Chin. Optics Lett., and J. on Sel. Topics in Quantum Electron. In 2021, Brandon was awarded the Kaminow Outstanding Early Career Professional Prize from Optica. In 2022, Brandon was selected to be a part of the 2022 Optica Ambassador class.
GDSfactory is a design automation tool for photonics and analog circuits. You can describe your circuits with a code driven flow (python or YAML), verify them (DRC, simulation) and analyze them. Multiple Silicon Photonics foundries have gdsfactory PDKs available. In this tutorial on GDSfactory, you will learn: ●Define parametric cells (PCells) in python or YAML ●Define routes between components ●Test component settings, ports and geometry to avoid regressions  Students, professors, research staff, and industry professionals gathered at Goleta Beach Area D to catch up, talk about photonics, and make new connections while enjoying excellent food. The brisket and pork shoulder from Prof. Schow was the highlight of the event. There was good conversation with industry members from Nexus Photonics, Freedom Photonics, Quintessent, HPE, and Praevium. Newer students got a chance to interact with current grad students and industry. Wendy Ibsen talked about outreach opportunities. The event was a great success with approximately 70 attendees.  
Abstract: As photonics matures beyond component-based devices, complex photonic integrated circuits are now being developed to meet commercial needs at the forefront of technology. Performance metrics are continually improved for lasers, modulators, multiplexers, detectors, and other important photonic components, but one capacity that has historically been challenging to scale is the optical wavelength. To develop a fully functional passive and active platform for wavelengths across the visible to near-IR brings additional challenges introduced by the various fabrication constraints of the different materials integrated on the same substrate. In this presentation Eric will discuss recent work on highly efficient nonlinear waveguides and on-going research to integrate a visible laser onto silicon chips with wide-band frequency conversion resonators. Next, he will motivate the need for improved performance of photonics to meet the demanding requirements for integrated quantum optics. Finally, a new application of nonlinear optics in the far-UVC for disinfection and Raman spectroscopy will be introduced. Bio: Eric Stanton attended Cal Poly San Luis Obispo, where he developed CubeSat nanosatellites and graduated with a B.Sc. in Electrical Engineering in 2012. During the summer of 2012 he worked at Agilent (now Keysight) before entering the graduate program at the University of California Santa Barbara (UCSB). In Professor John Bowers’ group, he developed integrated photonic technologies for a wide range of wavelengths from the visible to the mid-infrared. He obtained his Ph.D. in 2018 from the Electrical and Computer Engineering department at UCSB, and was awarded an NRC Postdoctoral Fellowship at the National Institute of Standards and Technology (NIST) in Boulder, CO. There he worked on nonlinear photonics and heterogeneously integrated lasers on silicon. Since 2020, he has been a CU Boulder PREP scientist at NIST. In 2021, he co-founded EMode Photonix, a photonics technology development company with the mission to make advanced photonic design tools more accessible.
About Infinera Infinera is a global supplier of innovative open optical networking solutions that enable carriers, cloud operators, governments, and enterprises to scale network bandwidth, accelerate service innovation, and automate network operations. Infinera solutions deliver industry-leading economics and performance in long-haul, submarine, data center interconnect, and metro transport applications. To learn more about Infinera, visit www.infinera.com, follow on Twitter and LinkedIn, and subscribe for updates. Robert Maher Bio: Robert Maher, Ph.D. serves as Sr. Director and Head of the Optical Systems Group at Infinera. He has authored over 100 technical publications in the field of optical transmission technologies. He was awarded the Marie Curie Research Fellowship from the European Research Council (ERC) in 2010 and the University Research Fellowship from the Royal Society, UK, in 2016. In recognition of his technical contributions to the optical industry, he has been awarded Optica’s Paul F Foreman Team Engineering Excellence Award and the Colin Campbell Mitchell Award from the Royal Academy of Engineering (UK). In 2015, he was elevated to Senior Member of the IEEE. Dr. Maher holds a B.Eng. in Electronic Engineering and a Ph.D. in Electronic Engineering from Dublin City University, Ireland. Dave Welch Bio: David F. Welch, Ph.D. co-founded Infinera in 2001, and serves as Chief Innovation Officer and member of the Board of Directors. He holds over 130 patents in optical transmission technologies, and has authored over 300 technical publications in the same field. In recognition of his technical contributions to the optical industry, he has been awarded the OSA’s Adolph Lomb Medal, Joseph Fraunhofer Award and John Tyndall Award, the IET’s JJ Thompson Medal for Achievement in Electronics, and the IEEE Ernst Weber Managerial Leadership Award. He is a Fellow of the OSA and the IEEE. In 2016, he was elected to the National Academy of Engineering. Dr. Welch holds a B.S. in Electrical Engineering from the University of Delaware and a Ph.D. in Electrical Engineering from Cornell University. Event Summary:
Dr. Robert Maher gave an overview of Infinera’s product solutions, the evolution of their coherent optical engine, and their latest ICE6 product. He discussed the integration of the electronic and photonic chips and the advantages of probabilistic constellation shaping for fine tuning the spectral efficiency for a given SNR. Dr. Dave Welch discussed the advantages of point-to-multipoint optical links in cost, flexibility, and network simplification. He described the operating principles of their XR Optics Transceiver in these optical links. Quantum wells in Nanowires for Optoelectronic Applications: Materials and Devices - Dr. Lan Fu6/15/2022
Thursday, June 23rd, 2:00 pm (PDT) -- Burgers from Kyle’s! Hosted in-person in Henley Hall 1010 Abstract – III-V compound semiconductor nanowires (NWs) have drawn much attention as nanoscale building blocks for integrated photonics/optoelectronics due to their nanoscale size, excellent optical properties and effectiveness in strain relaxation enabling the monolithic growth on lattice-mismatched substrates. In particular, NWs grown by selective area epitaxy technique have many advantages such as controllability of their size and position, high uniformity in diameter and length, as well as complementary metal-oxide-semiconductor (CMOS) process compatibility, facilitating their integration with other electronic devices. With suitable wavelength ranging from 1.3 to 1.6 μm and lattice match of constituent materials, InGaAs/InP quantum well (QW) has been being widely used for optical communication devices. However there has been limited understanding on the growth of InGaAs/InP QW in nanowire architecture and their application for optoelectronic devices such as lasers/LEDs and photodetectors. In this work, we present the study of the selective area epitaxy growth of InGaAs/InP multi-QW NW array by metalorganic chemical vapour deposition (MOCVD) technique, and the demonstration of nanowire LEDs/lasers and photodetectors with an investigation of their strong geometry related device properties by both numerical simulation and optoelectronic characterizations. Bio – Lan Fu received her PhD degree from the Australia National University (ANU) in 2001 and is currently a Full Professor at the Research School of Physics, ANU. Prof. Lan Fu was the recipient of the IEEE Photonic Society Graduate Student Fellowship (2000), Australian Research Council (ARC) Postdoctoral Fellowship (2002), ARF/QEII Fellowship (2005) and Future Fellowship (2012). Professor Fu is a senior member of IEEE, IEEE/Photonics and Electron Devices Societies and was the past chair of the Photonics Society, Electron Devices Society and Nanotechnology Council Chapters of the IEEE ACT section. She is the Chair of IEEE Nanotechnology Council Chapters & Regional Activities Committee, Associate Editor of IEEE Photonics Journal, and member of Editorial Board of Opto-Electronic Advances. She also the current member of the Australian Academy of Science National Committee on Materials Science and Engineering, Secretary of the Executive Committee of Australian Materials Research Society (AMRS), and Australian Research Council College of Experts. Professor Lan Fu’s main research interests include design, fabrication and integration of optoelectronic devices (LEDs, lasers, photodetectors and solar cells) based on low-dimensional III-V compound semiconductor structures including quantum wells, self-assembled quantum dots and nanowires grown by metal-organic chemical vapour deposition (MOCVD). Li, Z. Y., Tan, H. H., Jagadish, C., Fu, L., Adv. Mater. Technol. 2018, 3, 1800005. https://doi.org/10.1002/admt.201800005  On Friday, May 27 at 5pm, graduate students, UCSB professors, and representatives from 10 local photonics companies gathered for a night of food and networking at the UCSB Corwin Pavilion. The Banquet began with a recruitment pitch for the Photonics Society followed by talks from Thorlabs, Nexus Photonics, and Raytheon Vision Systems who are all major sponsors of the Photonics Society this year. Thanks to their generous support, the photonics society was able to host this event and many other small events at no cost to attendees. After a bountiful dinner, Professor Bowers co-hosted a talk with all of the companies in attendance to provide an overview of all the photonics opportunities in Santa Barbara. The presentation slides from Thorlabs, Nexus Photonics, Raytheon Vision Systems, and Professor Bowers can be accessed here. In his talk, Bowers showed work from Quintessent, OpenLight (prev. Aurrion), Morton Photonics, OE Solutions, Aeluma, Freedom Photonics, Ultra-Low Loss Technologies, Mirios, and Nexus Photonics. During his talk he passed the microphone to several of the industry members from these companies, giving them a chance to talk about their work. Industry members were excited to be back in person for networking and several were actively hiring students at the event. Thanks again to our Sponsors and Parent Organizations!Learn more about our sponsors by viewing their presentation slides.
Keynote Speaker - Dr. John BowersLearn more about Photonics in Santa Barbara by viewing the keynote presentation slides.  Dr. John Bowers is a world-leading researcher in the areas of silicon photonics, optoelectronics, energy efficiency and the development of novel low power optoelectronic devices for the next generation of optical networks. Dr. Bowers worked for AT&T Bell Laboratories and Honeywell before joining UC Santa Barbara. At UCSB, he holds the Fred Kavli Chair in Nanotechnology and is the Director of the Institute for Energy Efficiency and a Distinguished Professor in the Department of Electrical and Computer Engineering. His research interests include silicon photonics and integrated circuits, fiber optic networks, thermoelectrics, high efficiency solar cells, and optical switching. He is a cofounder of Aurrion, Aerius Photonics and Calient Networks. He has published two books, ten book chapters, 450 journal papers, 1000 conference papers and has received 54 patents. He and coworkers received the EE Times Annual Creativity in Electronics (ACE) Award for Most Promising Technology for the hybrid silicon laser in 2007.
Member of : National Academy of Engineering, National Academy of Inventors Fellow of: Institute of Electrical and Electronics Engineers (IEEE), Optical Society of America (OSA), American Physical Society (APS), American Association for the Advancement of Science (AAAS) Honors: Nick Holonyak, Jr. Award, Optical Society (OSA); IEEE Photonics Award; Tyndall Award (OSA/IEEE ); IEEE LEOS William Streifer Award; International Conference on Indium Phosphide and Related Materials (IPRM) Award; Highly Cited Researchers List, Web of Science Group; South Coast Business and Technology's Entrepreneur of the Year Affiliations: American Institute for Manufacturing Integrated Photonics, Institute for Energy Efficiency Education: PhD Stanford University MS Stanford University 
Friday, May 13th, 1:00 pm (PST) -- pizza provided! Hosted in-person in ESB 1001 and via Zoom Bio – Alexa Hudnut is an Optical Systems Engineer at Illumina in San Diego. Her research background is true to a Biomedical Engineer – a little bit of everything. She started her research in molecular biology and gene editing and then worked her way to instrumentation design and optics. She graduated with a PhD in Biomedical Engineering from the University of Southern California in 2018. She is most passionate about creating medical devices that leverage Optics and Materials Science for an intentionally sustainable future. Abstract – Illumina’s mission is to improve human health by unlocking the power of the genome. This translates to efforts such as tracking COVID variants, determining your dog’s breed, population genomics, and everything in between. Next generation sequencing (NGS) relies heavily on epifluorescence microscopy as the backbone of instrumentation. As we look toward the future of gene sequencing, it will become more prevalent as an in vitro diagnostic (IVD). To improve the clinical workflow, increased throughput is necessary for quicker turnaround times. These improvements are being driven by innovations such as structured illumination, multiplexing, image processing, and nanofabrication.
 Group photo of the QIS 2022 attendees outside Henley Hall The Photonics Society collaborated with the UCSB NSF Quantum Foundry to host industry partners and students for an in-person showcase event on April 22, 2022. The goal of the Quantum Industry Showcase (QIS) is to connect industry partners with the graduate students and postdocs working in quantum materials and technologies. With opportunities to ask questions and chat in-person, the event helps to foster discussion, mentoring, and recruitment. The event began with a keynote given by Kevin Roche of IBM followed by presentations from Hewlett Packard Enterprise, Cisco, and HRL. Attendees were able to ask questions and chat with industry partners during a panel session and a networking lunch. In the afternoon, representatives from Honeywell, Quantum Machines, and Quantinuum gave presentations. The event concluded after giving students the opportunity to showcase their work at a poster session. The Quantum Industry Showcase was attended by industry partners from Thorlabs, Quantinuum, Oxford Instruments NanoScience, Bleximo, HRL, Hewlett Packard Enterprise, IBM, Quantum Machines, Cisco, Honeywell, and Nexus Photonics. Prior to the QIS event, Thorlabs provided students with a tour of their facilities. The QIS event was sponsored in part by Oxford Instruments. For more information, visit 2022-qis.quantumfoundry.ucsb.edu
As part of the SBMA Free Community Day on April 7, 2022, the Photonics Society hosted a color mixing activity on the terrace in front of the art museum. Guests learned about additive and subtractive color mixing while having fun mixing paints. Several guests proved to be talented young artists, making beautiful recreations of Van Gogh paintings by mixing cyan, magenta, and yellow paint to create a variety of colors. 
Friday March 4th at 1:00pm PST in Henley Hall 1010 and via Zoom Pizza Provided in-person! Porous semiconducting nitrides are effectively a new class of semiconducting material, with properties distinct from the monolithic nitride layers from which devices from light emitting diodes (LEDs) to high electron mobility transistors are increasingly made. The introduction of porosity provides new opportunities to engineer a range of properties including refractive index, thermal and electrical conductivity, stiffness and piezoelectricity. Quantum structures may be created within porous architectures and novel composites may be created via the infiltration of other materials into porous nitride frameworks. A key example of the application of porous nitrides in photonics is the fabrication of high reflectivity distributed Bragg reflectors (DBRs) from alternating layers of porous and non-porous GaN. These reflectors are fabricated from epitaxial structures consisting of alternating doped and undoped layers, in which only the conductive, doped layers are electrochemically etched. Conventionally, trenches are formed using a dry-etching process, penetrating through the multilayer, and the electrochemical etch then proceeds laterally from the trench sidewalls. The need for these trenches then limits the device designs and manufacturing processes within which the resulting reflectors can be used. We have developed a novel alternative etching process, which removes the requirement for the dry-etched trenches, with etching proceeding vertically from the top surface through channels formed at naturally-occurring defects in the crystal structure of GaN. This etch process leaves an undoped top surface layer almost unaltered and suitable for further epitaxy. This new defect-based etching process provides great flexibility for the creation of a variety of sub-surface porous architectures on top of which a range of devices may be grown. Whilst DBR structures enable improved light extraction from LEDs and the formation of resonant cavities for lasers and single photon sources, recent development also suggest that thick, subs-surface porous layers may enable strain relaxation to help improve the efficiency of red microLEDs for augmented reality displays. Meanwhile, the option of filling pores in nitride layers with other materials provides new opportunities for the integration of nitrides with emerging photonic materials, such as the hybrid-perovskite semiconductors, with perovskites encapsulated in porous nitride layers demonstrating greatly improved robustness against environmental degradation.
Thursday, November 18th, 11 am (PST) in Henley Hall 1010 Pizza will be provided! Cutting edge diode lasers and PICs for sensing applications Over the past several years, many new application areas for photonics in optical sensing have opened up. In this talk, we will review record performance diode laser and PIC technology developed by Freedom Photonics for a variety of optical sensing applications - gas sensing, atomic sensing and LIDAR. Basic skills for a good technical team leader Many engineers with advanced degrees end up leading high-impact technical teams, in pursuit of research, development or production. In this talk, we will discuss various practical issues related to being a good team leader.
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