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Proceedings Paper

Radially-polarised beam amplification in an Yb:YAG thin-slab architecture (Conference Presentation)
Author(s): Callum R. Smith; Stephen J. Beecher; Jacob I. Mackenzie; W. Andrew Clarkson

Paper Abstract

Radially-polarised beams are attracting growing interest owing to their unique properties and numerous applications. Power-scaling whilst preserving the polarisation-purity of radially-polarised beams is challenging, with efforts predominantly focused on cylindrically-symmetric systems. We explore an alternative strategy for power-scaling radially-polarised beams using a thin-slab amplifier geometry, which, to the best of our knowledge, has not been previously investigated. We show that very high radial polarisation-purity can be maintained in an architecture that can be operated at high powers. A radially-polarised seed-source was constructed using an Yb:YAG rod in a plane-parallel configuration, pumped by a capillary delivery-fiber which provided effective overlap with the LG01 mode. By tuning the cavity length and utilising thermally-induced birefringence, a robust multi-Watt LG01 mode was generated with an excellent radial polarisation-purity of 15dB and good beam quality M2=2.2. The Yb:YAG slab was pumped by a diode-bar producing a highly-elongated inversion region. The seed was amplified in a double-pass configuration, using a cylindrical lens to spatially-match the inversion. The output beam was re-collimated by the cylindrical lens, and compensation for the Gouy phase-shift was made using a half-waveplate. At 50W of incident pump power we obtained a small-signal gain of 7.5dB and a power gain of 4.5dB for 1.45W seed power. At maximum pump power the radial polarisation-purity was maintained at 15dB, and the beam quality only degraded slightly to M2=2.3. Further optimisation of slab design and pump geometry will be discussed in addition to power-scaling the system to higher output powers necessary for a range of applications.

Paper Details

Date Published: 21 April 2017
PDF: 1 pages
Proc. SPIE 10082, Solid State Lasers XXVI: Technology and Devices, 1008204 (21 April 2017); doi: 10.1117/12.2256298
Show Author Affiliations
Callum R. Smith, Optoelectronics Research Ctr., Univ. of Southampton (United Kingdom)
Stephen J. Beecher, Optoelectronics Research Ctr., Univ. of Southampton (United Kingdom)
Jacob I. Mackenzie, Optoelectronics Research Ctr., Univ. of Southampton (United Kingdom)
W. Andrew Clarkson, Optoelectronics Research Ctr., Univ. of Southampton (United Kingdom)

Published in SPIE Proceedings Vol. 10082:
Solid State Lasers XXVI: Technology and Devices
W. Andrew Clarkson; Ramesh K. Shori, Editor(s)

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