
Proceedings Paper
On the efficiency of Tm-doped 2µm lasersFormat | Member Price | Non-Member Price |
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Paper Abstract
A potassium double tungstate layer with the composition KY0.40Gd0.29Lu0.23Tm0.08(WO4)2 was grown onto a pure KY(WO4)2 substrate by liquid-phase epitaxy, microstructured by standard lithography and Ar-ion etching, and overgrown by a pure KY(WO4)2 layer. The end-facets were polished. Laser experiments were performed on these buried, ridge-type channel waveguides in a resonator with one butt-coupled mirror and Fresnel reflection from the other end-facet, resulting in a high output-coupling degree of 89%, compared to intrinsic round-trip losses of only 2%. By pumping with a Ti:Sapphire laser at 794 nm, 1.6 W of output power at 1.84 μm with a maximum slope efficiency of ~80% was obtained. To the best of our knowledge, this result represents the most efficient 2-μm channel waveguide laser to date. We determined the optimum Tm3+ concentration in double tungstate channel waveguides to be at least 8at.% for efficient lasing. The theoretical limit of the slope efficiency depends on the Stokes efficiency which here is 43.2%, the outcoupling efficiency which here is 99%, and the pump quantum efficiency. The pump quantum efficiency of a 2-μm Tm3+ laser pumped around 800 nm hinges on the efficiency of its cross-relaxation process. By fitting the macroscopic cross-relaxation parameter which linearly depends on the Tm3+ concentration to concentration-dependent luminescence- decay data, calculating the overall decay rate of the pump level, and deriving the concentration-dependent pump quantum efficiency, we obtain a theoretical limit for the slope efficiency of 83% for the chosen Tm3+ concentration. The experimental slope efficiency of ~80% closely approaches this limit.
Paper Details
Date Published: 20 February 2015
PDF: 6 pages
Proc. SPIE 9342, Solid State Lasers XXIV: Technology and Devices, 93421U (20 February 2015); doi: 10.1117/12.2077490
Published in SPIE Proceedings Vol. 9342:
Solid State Lasers XXIV: Technology and Devices
W. Andrew Clarkson; Ramesh K. Shori, Editor(s)
PDF: 6 pages
Proc. SPIE 9342, Solid State Lasers XXIV: Technology and Devices, 93421U (20 February 2015); doi: 10.1117/12.2077490
Show Author Affiliations
K. van Dalfsen, Univ. Twente (Netherlands)
S. Aravazhi, Univ. Twente (Netherlands)
C. Grivas, Univ. of Southampton (United Kingdom)
S. Aravazhi, Univ. Twente (Netherlands)
C. Grivas, Univ. of Southampton (United Kingdom)
S. M. García-Blanco, Univ. Twente (Netherlands)
M. Pollnau, Univ. Twente (Netherlands)
KTH Royal Institute of Technology (Sweden)
M. Pollnau, Univ. Twente (Netherlands)
KTH Royal Institute of Technology (Sweden)
Published in SPIE Proceedings Vol. 9342:
Solid State Lasers XXIV: Technology and Devices
W. Andrew Clarkson; Ramesh K. Shori, Editor(s)
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