Speaker: Prof. Connie J. Chang-Hasnain (Dept. of Electrical Engineering and Computer Science Tsinghua Berkeley Shenzhen Institute University of California, Berkeley, CA  94720)

 

Time: Aug. 28, 2019 11:00AM 

 

Venue:No. 101 meeting room of the library, IOS, CAS  

 

Abstract：Vertical cavity surface emitting lasers (VCSELs) have long been predicted as low-cost enabling laser sources for many applications including optical communications, sensing and imaging. The VCSELs comprise a quantum well active region sandwiched between two highly reflective mirrors, all epitaxially grown on a GaAs or InP substrate. With the laser emitting in the surface normal direction, VCSELs enjoy the advantages offered by LEDs in wafer scale processing and easy of packaging.  The mirrors are typically distributed Bragg reflectors (DBRs) with many tens layers of epitaxy layers with alternating refractive indecies. Since 2004, we invented a single layer high index contrast near-wavelength gratings (HCG) to replace the hundred-layered DBR in a VCSEL structure.  Snice then, we develeoped a new class of planar optics has emerged using near-wavelength dielectric structures, known as high contrast metastructures (HCM).  Many extraordinary properties can be designed top-down based for integrated optics on a silicon or GaAs substrate. In this talk, I will review recent results using HCG as mirror for VCSEL as well as biosensor, 4-wave generation, and spatial light modulator.  I will discuss inventions and advances in VCSELs that have led to recent global deployment of commercial applications including 3D sensing, LIDAR and optical coherent tomography applications.  I will also discuss future prospects for advanced applications.

 

Biography:Connie Chang-Hasnain is Associate Dean for Strategic Alliances of College of Engineering and Whinnery Distinguished Chair Professor in Electrical Engineering and Computer Sciences, at the University of California, Berkeley.  Since 2015, she is the Founding Co-Director of Tsinghua-Berkeley Shenzhen Institute. Prior to joining the Berkeley faculty, Dr. Chang-Hasnain was a member of the technical staff at Bellcore (1987–1992) and Assistant Professor of Electrical Engineering at Stanford University (1992–1995). She is a fellow of IEEE, OSA and member of the National Academy of Engineering.

Professor Chang-Hasnain’s research interests include semiconductor optoelectronic devices, materials and applications.  She pioneered the first planar VCSEL structure using proton implantation for array fabrication with Gbps modulation, first MEMS-VCSEL for wavelegnth tuning, and the first 1000-elecment VCSEL arrays for 3D imaging. Prof. Chang-Hasnain has been honored with many awards including the Okawa Prize (2018), UNESCO Medal For the Development of Nanoscience and Nanotechnologies (2015), IEEE David Sarnoff Award (2011), and the OSA Nick Holonyak Jr. Award (2007). Additionally, she has been awarded with a Vannevar Bush Faculty Fellowship, a Humboldt Research Award, and a Guggenheim Fellowship.  She was a member of IEEE LEOS Board of Governors, OSA Board of Directors, and the Board on Assessment of NIST Programs, National Research Council. She was the Editor-in-Chief of Journal of Lightwave Technology 2007-2012. Professor Chang-Hasnain is the OSA Vice President in 2019.