Spiropyrane/Ethanol-Filled Plasma-Channal Photonic Crystal Fiber Sensor for Simultaneous Measurement of Ultraviolet Light and Temperature

Indole spiropyran is a kind of ultraviolet (UV) sensitive material with excellent properties. In this paper, a photonic crystal fiber (PCF) sensor with built-in nano-silver layer is proposed to generate dual sensing of Mach-Zehnder interference (MZI) and surface plasmon resonance (SPR) for simultaneous measurement of UV radiation and temperature. We use carbon dioxide laser etching to form holes on the side of PCF, and use silver mirror reaction to deposit nano-silver film in the internal holes of PCF, and use selective filling method to fill the ethanol dispersion of indole spiropyran into the air holes of PCF as UV and temperature sensitive materials. It has been verified that the sensor’s sensitivity to UV irradiation intensity can reach 0.8378 nm/mW/cm², and the sensitivity of temperature sensing can reach -0.6498 nm/oC. Based on two-parameter matrix demodulation, the simultaneous detection error of UV and sensor temperature of the sensor is less than 2%. The sensor has the advantages of compact size, straightforward, manufacture, and high sensitivity, and exhibits potential application prospects in the field of UV radiation detection.