Dome-shaped whispering gallery mode laser for remote wall temperature sensing

In this paper, we carried out experiments to investigate dome-shaped microlaser based on the whispering gallery modes for remote wall temperature sensing. The dome-shaped resonator was made of Norland blocking adhesive (NBA 107) doped with a solution of rhodamine 6G and ethanol. Two different configurations are considered: (i) resonator placed on top of a thin layer of 10:1 polydimethylsiloxane (10:1 PDMS), and (ii) resonator encapsulated in a thin layer of 10:1 PDMS. The microlaser was remotely pumped using a Q switch Nd:YAG laser with pulse repetition rate of 10 Hz, pulse linewidth of 10 ns, and pulse energy of 100  μJ/cm². The excited optical modes showed an average optical quality factor of 10⁴ for both configurations. In addition, the measurements showed sensitivity to temperature of ~0.06  nm/°C and a resolution of 1°C for both configurations. This sensitivity was limited by the resolution of the experimental setup used in these studies.