Ohmic thermal tuning optomechanical modes of optofluidic microbubble resonator

We fabricated an opto-mechano-fluidic microbubble resonator (MBR) consisting of a dielectric silica shell and liquid metal core. Benefiting from the conductivity of the liquid metal GaInSn, Ohmic heating was carried out for the MBR by applying current to the liquid metal to change the temperature of the MBR. Optical whispering gallery mode (WGM) and the optomechanical surface wave mode were tuned mainly because the Ohmic heating changed the refractive index and the Young's modulus of the silica, respectively. The optomechanical radial breathing mode was tuned mainly because the Ohmic heating changed the velocity and density of the liquid metal GaInSn. In our experiment, the WGM mode was tuned approximately 1.22 nm. The optomechanical surface wave mode and radial breathing mode were tuned approximately 0.30 MHz and 0.23 MHz, respectively.