Generation of High-Energy Geometric Structured Beams by Off-Axis Pumped Nd:YAG/Cr4+:YAG Lasers with Degenerate Resonators

Abstract

Off-axis pumped Nd:YAG/Cr4+:YAG lasers under degenerate cavity conditions are explored to achieve high-pulse-energy geometric modes for beam transformation. The employment of Nd:YAG crystal promises efficient passively Q-switched (PQS) operation with a flexible cavity length to ensure various PQS geometric modes with stable structures can be generated. It is experimentally confirmed that the output energy and peak power of the PQS geometric modes can easily reach up to over 100 mu J and 10 kW with fairly stable pulse trains in pure linear polarization. Various high-energy vortex beams carrying large angular momentum and diverse phase structures are achieved by converting the planar geometric modes into the circular ones to offer promising light sources for potential applications.