Examination of photonic crystal cavity structures

Photonic crystals are periodic optical structures that guide and confine the movement of photons. One of the most effective tools for this guidance and confinement is the use of cavity structures. Photonic cavity structures enable the precise control of many important parameters, such as frequency, light speed, and delays. Moreover, these structures play a critical role in enhancing light-matter interactions and improving the efficiency of photonic devices. Photonic crystal cavity structures form the foundation of numerous photonic devices, including optical sensors, optical logic gates, and both narrow and broad-band filters, in addition to applications like buffering and filtering of light. In this study, simulations were conducted to investigate the use of photonic cavity structures as coupled cavity waveguides. The effects of symmetry reduction on parameters such as frequency, group velocity, and group velocity dispersion (GVD) were analyzed using the plane wave expansion (PWE) and finite-difference time-domain (FDTD) methods. Specifically, we explored how symmetry breaking contributes to the phenomenon of rainbow trapping (RT). Rainbow trapping is a phenomenon where light of specific wavelengths is slowed and trapped at different positions, enabling applications such as optical delay lines and data storage. This study focuses on how the performance of photonic crystal cavity structures can be enhanced by combining low-symmetry effects with RT techniques. As a result of our work, both the improvement of optical parameters through low-symmetry effects and the successful realization of these improvements were achieved RT.