Opto-fluidic-plasmonic liquid-metal core microcavity

A hybrid microcavity based on the liquid-metal-filled silica microbubble is experimentally demonstrated, which supports both plasmonic and optical whispering gallery modes. The high quality (Q)-factor plasmonic mode of liquid metal is demonstrated via controlling the polarization of the probe laser as well as changing the liquids in the microbubble. Additionally, we reveal an unconventional Q-factor enhancement effect in the bottle microresonator. The liquid metal (mercury) could dissolve various metals and solids, meriting the optofluidic type of sensing. Combining the two kinds of high-Q resonances in the hybrid microcavity, we could probe the optical, mechanical, and thermal properties of solvents in liquid metal, providing a unique experimental platform for realizing multi-parameter optical sensing and making the detection and identification of metal and alloy possible.