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A high-power 2 crystal Nd:YLF laser at 1314 nm
R. C. Botha 1, 2, 3 , H. Strauss 2 , W. S. Koen 2 , C. Bollig 2 , W.L. Combrinck 1
1. Space Geodesy Programme, HartRAO, South Africa, roelf@hartrao.ac.za
2. Laser Sources Group, CSIR National Laser Centre, South Africa
3. Laser Research Institute, Stellenbosch University, South Africa
ABSTRACT
A new fundamental space geodetic observatory for South Africa has been proposed. Lunar Laser Ranging (LLR) is
one of the space geodetic techniques to be hosted on-site. LLR requires a pulsed laser that can operate at 100 to
400 mJ energy per ~ 20 pico-second pulses, at a pulse repetition frequency in the kHz region. It must also have
excellent beam quality at M 2 < 1.1. Since no commercial laser matching the exact specifications could be obtained,
it was decided to investigate into the possible development of such a laser.
The most feasible candidate for such laser parameters was found to be a crystal-based diode pumped system.
Nd:YLF was identified as a suitable candidate for the gain medium crystal. Investigating this material with is a 2crystal
system operating at 1314 nm rather than the usual 1053 nm, will be our last experimental setup. The
investigation primarily focuses on the power scaling of this material at this specific wavelength. A smaller (relative
to previous efforts) pump beam diameter of 1.0 mm is used to increase the efficiency. This however increases the
risk of thermal fracture. A total output power of this initial continuous wave laser is expected to be above 50 W.
KEYWORDS: High-power, pico-second, laser, ranging, lunar
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