Topologically-protected four-wave mixing enhanced by tailoring topological edge states

Laser pulse compression serves as a pivotal technique in nonlinear optics and light-matter interactions. Traditional methods, including Q-switching, mode-locking techniques, and chirped pulse amplification, are employed to generate high-intensity fields. However, these methods pose challenges when applied to topological lasers. In this study, we explore the pulse compression technique for topological edge states (TESs). Our findings reveal a significant correlation between the pulse width of TESs and their group velocity. Though factors such as nonlinear TES dispersion, disorders, and edge bending also affect pulse width, their impacts are comparatively less pronounced compared to that of group velocity. Through the customization of TES’s group velocity, we demonstrate a remarkable enhancement of four-wave mixing, showcasing it as a prime example of a nonlinear processing technique. Importantly, our approach promises seamless integration into topological laser systems, ensuring optimal performance with zero energy transfer loss and introducing a flexible dimension and robustness to topological nonlinear optical devices.