THEORETICAL STUDY ON OPTOTHERMAL OSCILLATION EFFECT OF MULTILAYER COMPOSITE WHISPERING GALLERY MICROCAVITY

Multilayer composite microcavity can achieve the unique phenomenon that can not be observed in single-material resonators. In this paper, the optothermal oscillation effect of silica microspheres coated with silk fibroin and polydimethylsiloxane (PDMS) is analyzed theoretically, and the unique oscillation waveform is observed. The waveform is composed of two oscillation with different periods, in which the slow oscillation contains several fast oscillation, and the fast oscillation only occurs in the temperature rise interval of silk fibroin and silica. We explain this phenomenon by constructing thermodynamics equations based on coupled-mode theory. The simultaneous phenomenon of oscillation may have potential applications value in sensitive detection.