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MSE Colloquium: Lan Yang

March 12, 2021 - 2:30pm to 3:50pm

Zoom password: 1234567890

Whispering-gallery-mode microresonators: fundamentals and applications

Lan Yang

Edwin H and Florence G. Skinner Professor in the Preston M. Green Department of Electrical and Systems Engineering at Washington University

Abstract: Light-matter interactions are the fundamental basis for many phenomena and processes in optical devices. Ultra-high-quality whispering-gallery-mode (WGM) optical micro-resonators provide the unprecedented capability to trap light in a highly confined volume smaller than a strand of human hair; light beams can travel around the boundary of a WGM resonator over 10 times, significantly enhancing light-matter interactions, creating the potential for a wealth of new scientific discoveries and technological breakthroughs difficult to achieve by other devices. They have shown great promise for a variety of fields of science, spanning from optomechanics to communication, non-Hermitian physics, sensing and metrology. In this talk, I will report the recent research discoveries from my group in this exciting field. I will present a few cases demonstrating the great potentials of high-Q WGM microreonators and microlasers for both fundamental science and engineering applications. Specifically, I will discuss ultra-high-Q microresonators and microlasers for ultra-sensitive detection of nanoscale objects. I will explain a self-referencing sensing scheme for a detection and sizing of single nanoparticles and present our recent study in utilizing the spectra of high-Q resonator as barcodes for high-precision and wide-range temperature measurements. These advancements in WGM mircoresonators will enable a new class of ultra-sensitive and low-power sensors for investigating the properties and kinetic behaviors of nanomaterials, nanostructures, and nanoscale phenomena. Afterwards, I will discuss our exploration of fundamental physics, such as parity-time symmetry (PT-symmetry) and light-matter interactions around exceptional points (EPs) in high-quality WGM resonators, which can be used to achieve a new generation of optical systems enabling unconventional control of light flow. Examples including nonreciprocal light transmission, loss engineering in a lasing system, directional lasing emission, and EPs enhanced sensing will be introduced. A non-Hermitian photon laser tuned in the vicinity of EPs will be discussed briefly. In the end. I will present a new generic and hand-held microresonator platform transformed from a table-top setup, which will help further unleash the power of high-Q WGM resonator technologies. 

Bio: Professor Lan Yang is the Edwin H. and Florence G. Skinner professor in the Preston M. Green Department of Electrical and Systems Engineering at Washington University, St. Louis, MO. USA. She received her B.S. from the University of Science and Technology of China and graduated from Caltech in 2005 with a PhD in applied physics. Her research interests have been focusing on the fundamental understanding of high-quality photonic whispering-gallery-mode (WGM) resonators ad their applications for sensing, lasing, light harvesting, and communications. Recently, her research interests expanded to a parity-time-symmetry and non-Hermitian physics in high-quality WGM resonators, which have led to a series of new discoveries for unconventional control of light transport in photonic structures. She received NSF CAREER Award in 2010 for her work on single nanoparticle detection and sizing using an on-chip optical resonator. She is also the recipient of the 2010 Presidential Early Career Award for Scientists and Engineers (PECASE). She is the editor-in-chief of Photonics Research and also a Fellow of OSA, IEEE, APS, and AAAs. 

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Materials Science and Engineering
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