Ultraslow light effect driven by quasibound states in the continuum in compound grating waveguide structures

Slow light effect plays a crucial role in both optical physics and devices. Herein, we explore the possibility to achieve ultraslow light effect based on the quasibound states in the continuum (quasi-BICs) in a compound grating waveguide structure. Driven by the unique resonant property of the quasi-BIC, the group velocity of light can be intensively slowed down to the order of 10-4c. Interestingly, we disclose that the group velocity of light and geometric perturbation parameters conforms to double-logarithm linear relationship. Our findings not only offer unique insight for the relation between slow light effect and BIC, but also provide a feasible route to achieving ultraslow light effect.

Automated summary

This study explores the possibility of achieving ultra-slow light effect in a compound grating waveguide structure, and discovers a double-logarithmic linear relationship between the group velocity of light and geometric perturbation parameters.