High-sensitivity temperature sensor using the ultrahigh order mode-enhanced Goos-Hänchen effect.

A high-sensitivity temperature sensor based on the enhanced Goos-Hänchen effect in a symmetrical metal-cladding waveguide is theoretically proposed and experimentally demonstrated. Owing to the high sensitivity of the ultrahigh-order modes, any minute variation of the refractive index and thickness in the guiding layer induced by the thermo-optic and thermal expansion effects will easily give rise to a dramatic change in the position of the reflected light. In our experiment, a series of Goos-Hänchen shifts are measured at temperatures varying from 50.0 °C to 51.2 °C with a step of 0.2 °C. The sensor exhibits a good linearity and a high resolution of approximately 5×10(-3) °C. Moreover, there is no need to employ any complicated optical equipment and servo techniques, since our transduction scheme is irrelevant to the light source fluctuation.