Photoelastic tuning of photonic band gaps in cylindrical multilayers: periodic and Fibonacci configurations

This work investigates light propagation in one-dimensional cylindrical photonic crystals (CPCs) using the transfer matrix method for periodic and Fibonacci sequences. The effects of externally applied mechanical pressure are modeled by simultaneously considering the photoelastic modification of the refractive indices and the elastic deformation of the silicon and polystyrene layers. The results show that increasing the pressure from 0 to 3 gigapascals (GPa) shifts the photonic band gaps toward higher reduced frequencies owing to pressure-induced changes in the effective optical thickness of the structure. In addition, pressure modifies the widths of the photonic band gaps, producing a slight narrowing of the central band gap in the periodic crystal, whereas the Fibonacci structures exhibit a more complex response, with the first band gap broadening and the second becoming progressively narrower. These findings demonstrate that mechanical pressure can effectively tune the spectral position and width of photonic band gaps, providing a theoretical basis for the future development of pressure-tunable photonic devices.