Simple Coherent Polarization Manipulation Scheme for Generating High Power Radially Polarized Beam

TL;DR

This paper introduces a simple, stable method for converting Gaussian beams into high-power radially polarized beams using birefringent crystals, avoiding complex interferometers and enabling high-power applications.

Contribution

A novel, stable scheme for radially polarized beam generation using coherent polarization manipulation with birefringent crystals, reducing interferometric stability requirements.

Findings

Generated 14 watts of radially polarized beam.

Scheme is stable even with short laser coherence length.

Power limited only by available fiber laser power.

Abstract

We present a simple novel scheme that converts a Gaussian beam into an approximated radially polarized beam using coherent polarization manipulation together with Poynting walk-off in birefringent crystals. Our scheme alleviates the interferometric stability required by previous schemes that implemented this coherent mode summation using Mach-Zehnder-like interferometers. A symmetrical arrangement of two walk-off crystals with a half-wave plate, allows coherence control even when the laser has short temporal coherence length. We generated 14 watts of radially polarized beam from an Ytterbium fiber laser, only limited by the available fiber laser power.