Deng Yang, Liu Fenfei, Leseman Zayd C, Hossein-Zadeh Mani
Department of Electrical and Computer Engineering and Center for High Technology Materials (CHTM), University of New Mexico, Albuquerque, New Mexico 87106, USA.
Opt Express. 2013 Feb 25;21(4):4653-64. doi: 10.1364/OE.21.004653.
We demonstrate and characterize a thermo-optomechanical oscillator based on a PMMA-coated silica microtoroid and employ it as a sensor. The observed thermo-optomechanical oscillation has a unique waveform that consists of fast and slow oscillation periods. A model based on thermal and optical dynamics of the cavity is used to describe the bi-frequency oscillation and experiments are conducted to validate the theoretical model in order to explore the origin of the two oscillatory phenomena. As opposed to previously shown hybrid toroidal microcavities, the excessive PMMA coating boosts the thermo-mechanical (expansion) effect that results in bi-frequency oscillation when coupled with the thermo-optical effect. The influences of the input power, quality factor, and wavelength detuning on oscillation frequencies are studied experimentally and verified theoretically. Finally the application of this oscillator as a sensor is explored by demonstrating the sensitivity of oscillation frequency to humidity changes.
我们展示并表征了一种基于聚甲基丙烯酸甲酯（PMMA）涂层二氧化硅微环面的热光机械振荡器，并将其用作传感器。观察到的热光机械振荡具有独特的波形，由快速和慢速振荡周期组成。基于腔的热动力学和光学动力学的模型用于描述双频振荡，并进行实验以验证理论模型，从而探究这两种振荡现象的起源。与先前展示的混合环形微腔不同，过量的PMMA涂层增强了热机械（膨胀）效应，当与热光效应耦合时会导致双频振荡。通过实验研究了输入功率、品质因数和波长失谐对振荡频率的影响，并从理论上进行了验证。最后，通过展示振荡频率对湿度变化的敏感性，探索了该振荡器作为传感器的应用。
