Recent developments of the micro-pulling down technique lead to efficient laser demonstration with Nd:YAG single crystal fibers. Indeed these media which benefit from the spectroscopic and thermal properties of bulk crystals and from the thin and long shape of glass fibers are ideal candidates for high average and high peak power laser systems. In this work, we investigate the potential of Yb:YAG single crystal fibers. After a careful design taking into account the quasithree level structure of the Yb³⁺ ions, we grew single crystal fibers by the micro-pulling down technique. With a 1 at.% doped and 40 mm long single crystal fiber of 1 mm in diameter, we obtained a power of 50 W in CW operation under 200 W of incident pump power. In the Q-switched regime, we achieved pulses with an energy of 1.8 mJ at 5 kHz and a duration of 13 ns for 120 W of pump power. We measured a M² value below 2.5. We also investigated the thermal management of our system by the use of thermal cartography and Finite Element Analysis, showing a maximum temperature smaller than 120°C reached on the pumped end face for 200 W of pump power. These results are a very promising to design high average power and high peak power laser sources.

Date Published: 27 February 2009
PDF: 8 pages
Proc. SPIE 7193, Solid State Lasers XVIII: Technology and Devices, 71930L (27 February 2009); doi: 10.1117/12.807918

Published in SPIE Proceedings Vol. 7193:
Solid State Lasers XVIII: Technology and Devices
W. Andrew Clarkson; Norman Hodgson; Ramesh K. Shori, Editor(s)