All-optical tuning of a magnetic-fluid-filled optofluidic ring resonator

作者:Liu, Yang; Shi, Lei*; Xu, Xinbiao; Zhao, Ping; Wang, Zheqi; Pu, Shengli; Zhang, Xinliang
来源:Lab on a Chip, 2014, 14(16): 3004-3010.
DOI:10.1039/c4lc00236a

摘要

An all-optical tunable optofluidic ring resonator (OFRR) is proposed and experimentally demonstrated. The all-optical control of a silica microresonator is highly attractive, but it is difficult to realize because of the relatively weak Kerr effect and the absence of a plasma dispersion effect of silica. Here, we infuse a silica microcapillary-based optofluidic ring resonator with a magnetic fluid, into which pump light is injected by a fiber taper. Iron oxide nanoparticles dispersed in the magnetic fluid produce a strong pump light absorption, and this leads to a resonance shift of the silica microresonator due to the photothermal effect. To the best of our knowledge, this is the first scheme for all-optical tuning of an OFRR. A tuning sensitivity of up to 0.15 nm mW(-1) and a tuning range of 3.3 nm are achieved. With such excellent performance, the magnetic-fluid-filled OFRR has great potential in filtering, sensing, and signal processing applications.