报告题目： Whispering-Gallery Microresonators and Microlasers for nanoscale sensing and beyond
时 间：2015年7月6日（周一) 上午10:00—11:00
报告人概况：杨兰，美国圣路易斯华盛顿大学电子系教授（Edwin H. & Florence G. Skinner Professor），毕业于中国科技大学少年班，2005年于美国加州理工大学获得博士学位。其研究组主要从事微纳尺度光子器件的制备、表征，硅基光学微腔传感等方面的研究。近年来在Science, Nature Physics, Nature Photonics, Nature Communications, Nature Nanotechnology, PNAS等期刊发表了一系列开创性的研究工作。杨兰教授于2011年获得由奥巴马总统颁发的总统奖（PECASE），现担任Optics Express等多个SCI期刊编委。
Light-matter interactions are the fundamental basis for many phenomena and processes in optical devices. In this talk I will introduce and explain ultra-high-quality (Q) optical Whispering-Gallery-Mode(WGM) microresonators, in which light-matter interactions are significantly enhanced due to their superior capability to trap light field in a highly confined volume with low loss. WGM resonators have shown great promise for a variety of fields of science, spanning from atom-resonator coupling and optomechanics to on-chip microresonator lasers and ultra-sensitive label-free bio-chemical sensing. In this talk, after briefly introducing the physical concepts of WGM microresonators, I will report recent progress in our group towards developing functional platforms using high-Q WGM microresonators and microlasers. First, I will present a recent discovery in using ultra-high-Q microresonators and microlasers for ultra-sensitive self-referencing detection and sizing of single virion, dielectric and metallic nanoparticles. I will also discuss using optical gains in a microlaser to improve the detection limit beyond the reach of a passive microresonator. These recent advancements in WGM microresonators 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. Then I will present an interesting hybrid nanoparticle-resonator system in which the nanoparticles open a new channel to couple light from free space into high-Q WGM resonators. You will see two types of lasers, Raman and rare-earth-ions doped microlasers, achieved by free-space pumping of high-Q resonators via the nanocouplers. In the end, I will discuss exploration of fundamental physics, such as parity-time symmetry and light-matter interactions around exceptional point (EP) in high-quality WGM resonators, which can be used to achieve a new generation of optical systems enabling unconventional control of light flow.