Thermal and laser properties of Yb:LuAG for kW thin disk lasers

Abstract

Thin disk laser experiments with Yb:LuAG (Yb:Lu(3)Al(5)O(12)) were performed leading to 5 kW of output power and an optical-to-optical efficiency exceeding 60%. Comparative analyses of the laser relevant parameters of Yb:LuAG and Yb:YAG were carried out. While the spectroscopic properties were found to be nearly identical, investigations of the thermal conductivities revealed a 20% higher value for Yb:LuAG at Yb(3+)-doping concentrations of about 10%. Due to the superior thermal conductivity with respect to Yb:YAG, Yb:LuAG offers thus the potential of improved performance in high power thin disk laser applications.

Yb:YAG planar waveguide lasers grown by pulsed laser deposition: 70% slope efficiencies at 16 W of output power

“…From this fluorescence spectrum we then use the Früchtbauer-Landenburg equation to calculate the emission cross-section for the material. As previously reported for our growth from an uncompensated target we see a significant reduction of fluorescence at 1030 nm in comparison to Czochralski grown Yb:YAG,, while for our Al compensated film this has been almost completely rectified with the measured data very close to that reported for Czochralski grown Yb:YAG by Beil et al 17 . Figure 3.…”

“…Figure 3. Spectroscopy of the guide reported in 16 , the Al compensated guide reported here and the spectroscopy from a Czochralski grown sample reported in 17 .…”

Towards a Compact Thin-Disk-Based Femtosecond XUV Source

“…The pump absorption can be kept constant by choosing a material with higher doping level and reducing its thickness. Unfortunately, the doping level cannot be strongly increased because of the concentration quenching and reduced thermal conductivity [57]. Thus, these two issues should always be addressed in choosing a crystal for thin-disk operation.…”

121 W passively mode-locked Tm:LuAG laser

“…For example, the thermal conductivity of 4% Tm:LuAG is about the same as 4% Tm:YAG even though the pure LuAG has a thermal conductivity only 60% that of YAG [22]. In addition, LuAG is harder than YAG, which is believed to have a higher damage threshold [23]. Up to now, a maximum average output power of 4.91 W has been achieved from a continuous wave (CW) Tm:LuAG laser [24].…”