Ultrasensitive Pressure Sensor Based on Point Defect Resonant Cavity in Photonic Crystal

This paper discusses the theoretical analyze and design of two-dimensional (2D) photonic crystal (PhC) pressure sensor with high sensitivity and resolution. The sensor consists of a waveguide directly coupled to a nanocavity that is formed by modifying the radius of one air hole at the center of lattice. The finite difference time domain (FDTD) method is used to calculate the resonant wavelength of the nanocavity in different pressures. The simulation results show that resonant wavelength of nanocavity is shifted to longer wavelength by increasing of applied pressure. The sensitivity of the sensor is obtained as 11.7 nm/GPa and minimum detectable force is given as 13 nN. Also, the resonant wavelength in zero-pressure and the quality factor of resonant peak are respectively obtained as 1496.1 nm and 11508.46. The results are briefly compared with those previously reported for sensitivity, central wavelength, quality factor, and minimum detectable force.