Biocompatible miniature temperature sensor based on whispering gallery modes of Sm3+ activated ZnO optical micro-resonators

Abstract

Toward achieving an efficient micro-optical temperature sensor in a wide visible spectral range, Sm3+:ZnO micro-spheres are fabricated by the laser ablation technique. Visible range whispering gallery mode resonances are observed and are found to be lasing above low optical threshold with a quality factor of the order of 103. A temperature-induced change in whispering gallery modes is observed with a sensitivity of 0.04 nm/°C from the micro-sphere of diameter 10.5 μm. Using these results, cost-effective and bio-compatible miniature temperature sensors that operate in the visible spectral range could be devised.