Suppression of Higher-Order Transverse Modes in a Nd:YVO4 Laser Using Hard and Soft Aperturing
AUG 14, 2026
JURPA 2026 Cover Image.
Abstract. Laser resonators possess higher-order transverse modes (HOTMs) corresponding to solutions of Maxwell’s equations within cavity boundary conditions. Thermal lensing at high pump powers in the gain medium can facilitate HOTMs, creating nonuniform intensity profiles that are detrimental if the laser drives nonlinear processes. This study investigates two methods of inhibiting HOTM onset: an intracavity iris (“hard” aperture) and a reduced pump laser radius (“soft” aperture). Data show that for 808-nm input power between 0 and 7.145 W, a hard aperture eliminates HOTMs, decreasing slope efficiency by 65.3%, whereas a soft aperture delays HOTM appearance, increasing slope efficiency by 11.0%.
