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Q-switched laser with self-mode-filtering interferometric vortex output coupler

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Title: Q-switched laser with self-mode-filtering interferometric vortex output coupler
Authors: Geberbauer, J
Kerridge-Johns, WR
Damzen, MJ
Item Type: Journal Article
Abstract: Vortex lasers are an attractive prospect for efficient generation of high-quality beams in compact, environmentally robust, and turnkey systems. We demonstrate conversion of a Q-switched, diode-pumped Nd:YVO4, TEM00 Gaussian laser into a vortex laser source by replacing the output coupling mirror by a vortex output coupler (VOC) based on an imbalanced Sagnac interferometer. The Q-switched VOC laser generated a vortex output with 5.1 W average power, slope efficiency of 46% at 150 kHz pulse repetition rate, only marginally lower than the 5.4W and 49% slope efficiency of the plane mirror laser. Vortex handedness was switchable with a single VOC control without loss of vortex power. In both handedness cases, the vortex mode quality was assessed to be excellent by detailed analysis of the vortex phase profile and propagation characteristics and comparison to an ideal vortex. Further investigation verified the ability for the VOC laser to self-mode-filter the intracavity mode, showing maintenance of high TEM00 quality even after introducing deliberate mode to pump size mismatch, when the equivalent plane mirror laser becomes multimode. This work highlights the potential of the VOC as a simple route to high powered structured light sources using just standard high-power handling mirror components and its self-mode-filtering property to compensate intra-cavity spatial mode degradation when power-scaling.
Issue Date: 15-Feb-2020
Date of Acceptance: 8-Jan-2020
URI: http://hdl.handle.net/10044/1/76870
DOI: 10.1364/osac.384837
ISSN: 2578-7519
Publisher: Taylor & Francis
Start Page: 204
End Page: 213
Journal / Book Title: OSA Continuum
Volume: 3
Issue: 2
Copyright Statement: © The Author(s) 2020. Published by The Optical Society under the terms of the Creative Commons Attribution 4.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI
Sponsor/Funder: Engineering & Physical Science Research Council (E
Commission of the European Communities
Funder's Grant Number: EP/R511547/1
Publication Status: Published
Online Publication Date: 2020-01-17
Appears in Collections:Mechanical Engineering
Faculty of Natural Sciences