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Proceedings Paper

Tandem OPO systems for mid-infrared generation using quasi phase-matching and volume Bragg gratings
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Paper Abstract

Efficient laser sources in the 3 - 5 μm wavelength range are needed for directed infrared countermeasures, but also have applications in remote sensing, medicine and spectroscopy. We present results and discuss the possibilities of a tandem optical parametric oscillator (OPO) scheme for converting the radiation from a 1.06 μm Nd3+-laser to the mid-infrared. Our setup uses type I quasi phase-matched (QPM) crystals in a near degenerate OPO to generate 2.13 μm radiation. The QPM crystal provides higher nonlinearity and longer interaction lengths, because walk-off is avoided, compared to conventional bulk crystals. This is an advantage especially in low pulse energy applications. To make the 2.13 μm radiation usable for pumping a second OPO a volume Bragg grating is used as a cavity mirror to limit the bandwidth, which in a conventional QPM OPO at degeneracy can be several hundred nanometers. The acceptance bandwidth for efficient OPO operation of a 14 mm long ZnGeP2 (ZGP) crystal is approximately 5 nm, which makes the need for bandwidth limiting clear. The majority of the signal energy from a periodically poled KTiOPO4 (PP KTP) OPO with a volume Bragg grating output coupler was found to be in a single longitudinal mode, whereas the idler bandwidth was measured to 19 GHz (FWHM). A volume Bragg grating resonant near 2124 nm was chosen so that the signal and idler were separated by 9 nm. This OPO output has been used as a pump source for a conventional ZGP OPO demonstrating efficient conversion and providing broadband tunable output in the mid-infrared.

Paper Details

Date Published: 11 October 2007
PDF: 11 pages
Proc. SPIE 6738, Technologies for Optical Countermeasures IV, 673805 (11 October 2007); doi: 10.1117/12.737229
Show Author Affiliations
Markus Henriksson, Swedish Defence Research Agency (Sweden)
Royal Institute of Technology (Sweden)
Lars Sjöqvist, Swedish Defence Research Agency (Sweden)
Mikael Tiihonen, Kungliga Tekniska Högskolan (Sweden)
Valdas Pasiskevicius, Kungliga Tekniska Högskolan (Sweden)
Fredrik Laurell, Kungliga Tekniska Högskolan (Sweden)

Published in SPIE Proceedings Vol. 6738:
Technologies for Optical Countermeasures IV
David H. Titterton; Mark A. Richardson, Editor(s)

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