Ultrasensitive and Visual Gas Pressure Sensor Based on a Tunable Fabry–Pérot Resonator

Gas pressure sensors are essential in industrial and environmental monitoring. In this study, we propose and demonstrate an ultrasensitive and visually detectable gas pressure sensor based on a tunable Fabry–Pérot (FP) resonator. The FP resonator is composed of a suspended polydimethylsiloxane/palladium (PDMS/Pd) bilayer on a Pd square hole array. When subjected to external gas pressure, the suspended bilayer is concave downward and thus reduces the length of the FP cavity, resulting in a blue shift of the reflection peak. The proposed sensor exhibits an ultrahigh sensitivity of 69.6 nm/kPa above atmospheric pressure, which is easily visualized due to the large spectral shift in the visible band. In addition, this sensor has a low detection limit of 0.1 kPa and good recyclability, indicating that our sensor has great potential for low gas pressure measurement applications.