Transverse-mode control in VCSEL with an intra-cavity metalens

This paper presents a comprehensive numerical analysis of an 850 nm vertical-cavity surface-emitting laser (VCSEL) integrated with intra-cavity metalens. Utilizing the finite-difference time-domain (FDTD) method, we develop a three-dimensional model to examine the impact of an intra-cavity metalens on the modal behavior of the VCSEL. The metalens is designed to converge the fundamental mode towards the central region of the VCSEL cavity. Together with employing a half-cavity VCSEL structure and tailoring the top DBR reflectivity through dielectric DBR evaporation, we achieve a large threshold gain gap between the fundamental mode and higher-order modes, which should enable single-mode operation and high output for VCSELs with large aperture diameters.