Ultra-High-Order Laguerre-Gaussian Mode Output Based on Annular Pumping and Intra-Cavity Lens

Abstract

This letter presents an experimental study on generating ultra-high-order Laguerre-Gaussian (LG) modes in an Nd:YAG solid-state laser using annular pumping and an intra-cavity lens. The hollow structure of the annular pump beam effectively suppresses low-order modes, creating optimal conditions for high-order modes excitation. The intra-cavity convex lens enhances single-mode selection, enabling stable ultra-high-order petal-like ${\mathrm {LG}}_{{0,\pm }{l}}$ mode output. By adjusting the pump beam size and lens position, the highest angular indices l reached 375th order was achieved. This approach provides a novel method for high-order ${\mathrm {LG}}_{{0,\pm }{l}}$ mode generation in solid-state lasers, with potential applications in optical manipulation, optical communication, and related fields.