"Asymmetric whispering gallery microcavity optics and photonics" Yun-Feng Xiao

Speaker:
Professor Yun-Feng Xiao, State Key Lab for Mesoscopic Physics, Peking University, P. R. China

Seminar Title:
Asymmetric whispering gallery microcavity optics and photonics

Abstract:
Confinement and manipulation of photons using microcavities have triggered intense research interest in both basic and applied physics for more than one decade. Prominent examples are whispering gallery microcavities which confine photons by means of continuous total internal reflection along a curved and smooth surface. The long photon lifetime, strong field confinement, and in-plane emission characteristics make them promising candidates for enhancing light-matter interactions on a chip. In this talk, we report experimentally a new type of on-chip whispering gallery microcavity which supported both highly unidirectional emission and ultra-high-Q factors exceeding 100 million in near infrared. By doping erbium, the unidirectional-emission lasing was observed in 1,550 nm band with the threshold as low as 2 microwatts. Moreover, we propose a sensing mechanism by monitoring mode broadening in microcavities, which is immune to both noise from the probe laser and environmental disturbances, and would remove the strict requirement for ultra-high-Q mode cavities for sensitive nanoparticle detection.