Ultrasensitive label-free coupled optofluidic ring laser sensor

作者:Ren, Liqiang; Wu, Xiang*; Li, Ming; Zhang, Xingwang; Liu, Liying; Xu, Lei
来源:Optics Letters, 2012, 37(18): 3873-3875.
DOI:10.1364/OL.37.003873

摘要

A coupled optofluidic ring laser sensor is fabricated, and its ultrasensitive bulk refractive index and surface mass sensing properties are demonstrated. The sensor consists of a cylindrical ring laser and a thin-walled optofluidic capillary ring resonator. Coupling of the whispering gallery mode in the two resonators generates a largely magnified sensitivity due to the Vernier effect. A sensitivity of 2510 nm/RIU and magnification factor of 355 are achieved experimentally in aqueous solution, which corresponds to a noise equivalent detection limit of 1.6 x 10(-5) RIU for bulk RI detection. The new sensor configuration provides a convenient way to achieve ultrasensitive biological and chemical sensing.