Femtosecond Laser Microprinting of a Fiber Whispering Gallery Mode Resonator for Highly-Sensitive Temperature Measurements

We demonstrate a novel method for producing whispering gallery mode (WGM) resonators on a microfiber using femtosecond laser two-photon polymerization technology. The typical resonance was observed by coupling the microresonator with a tapered fiber in a region where they were physically separated. Unlike conventional WGM devices, this photosensitive resin-based resonator was deposited on a microfiber, whereby the structural integration was improved. Resonance was experimentally demonstrated using two types of ring structures, i.e., circle and racetrack. The devices were successfully used for temperature measurements, achieving a maximum temperature sensitivity of 1.68 nm/ °C and a Q-factor of 1.9 × 10
³
.