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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 
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.
 Join us at Henley Hall 1010 on 10/28 at 1pm! Free Pizza Provided!
Dr. Julia Majors - Master Oscillator Packaging for the Laser Interferometer Space Antenna (LISA)7/8/2021
Thursday, July 15, 10:00 - 11:00 am (PDT) 5 years after the earth-based gravitational wave observatory, LIGO, made its first detection of gravitational waves, work is already well underway in preparing for the next generation of gravitational wave observatories – in orbit around the sun. Working with NASA Goddard Space Flight Center, we are building what will be the “quietest” oscillator in (and above) the world to serve as the core light source for the interferometric system. The system is based on a non-planar ring oscillator (NPRO) model, which I will discuss along with some of the challenges that arise when developing laser systems for space applications. Student Lecture by KaiKai Liu on Milliwatt Threshold 0.5-Hz Linewidth Si3N4 Brillouin Laser5/25/2021
 Friday May 28 at 1:00 pm
 The UCSB Quantum Foundry and the UCSB Photonics Society hosted the 2021 Quantum Industry Showcase on April 22 and 23. You can watch the Keynote address and the fireside chat below. You can also find more information and presentations from the event at https://qis.quantumfoundry.ucsb.edu/. Like these videos? Watch the full QIS 2021 playlist at
https://www.youtube.com/watch?v=xulQc4G_R9w&list=PLtIKDPzlP_wMvxVLMWlnP-lP6kb7Lr29l  1:00 PM Friday, April 2nd
Thursday, February 25th, 10 am (PST) via Zoom Meeting ID: 854 2977 2482 Passcode: 230903 Both human vision and imaging systems have limited capability to separate spatial features, and this information can only be extracted from a limited range in depth. These limitations arise from diffraction, i.e., the finite dimensions of the imaging optics and the geometry of the sensor. In this talk, I will present novel photonic approaches to exceed the resolution limitations of geometric optics. I will show how those concepts can be adapted to micro endoscopy as well as to microscopy-related configurations, including ophthalmic devices for correcting visual deficiencies.
Friday, January 29th, 10 am (PST) Infrared detectors and imaging systems are becoming increasingly important in a diverse range of astronomic, military, and civilian applications. This field has gained significant attention while incorporating various materials and architectures into detector designs with a strong focus on applicability into clinical domains. Dr. Perera will discuss recent detector structures, and his latest work on disease detection. Biomedical applications of infrared include an exploration of an Affordable, Sensitive, Specific, User-friendly, Rapid, Equipment-free, and Deliverable (ASSURED) diagnostic regimen and testing its clinical feasibility for inflammatory bowel diseases (IBDs) and cancer screening. A study using Fourier transform infrared (FTIR) spectroscopy in attenuated total reflectance (ATR) sampling mode analyzed body fluids in order to identify reproducible, stable, and statistically significant differences in spectral signatures of the IR absorbance spectra between the control and disease samples. These results show that serum samples can be used to detect the biochemical changes induced by these diseases.
 1:00 PM Friday, January 22nd |
 Yahya Mohtashami Schuller group ECE Dept, UCSB |
In this talk, we show that we can increase the light extraction efficiency of, impart directionality upon, collimate, and focus the spontaneous emission from InGaN/GaN quantum wells, using phased-array metasurfaces. |
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Strong THz laser fields can explore non-linear, non-equilibrium phenomena in matter. The talk will focus on photons emitted by electron/hole re-collisions, and how the polarization of these photons carries information about the semiconductor. |
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