Sensitivity Characteristics of Microfiber Fabry-Perot Interferometric Photoacoustic Sensors

A microfiber Fabry-Perot (FP) interferometer is proposed for photoacoustic sensing. It is fabricated by utilizing the 193 nm UV exposure and the phase mask technique. Two fiber Bragg gratings which are formed in a microscaled optical fiber as a FP cavity serves as a sensor. In contrast to the conventional, new characteristics are attributed to the microfiber segment of the refractive index change. The microfiber FP interferometric photoacoustic sensor dependencies on acoustic pressure, temperature, and refractive index are investigated. This compact photoacoustic sensor, with the diameter of microns, is suitable for photoacoustic imaging, especially in photo acoustic microtomography.