Puncken Oliver, Tünnermann Henrik, Morehead James J, Wessels Peter, Frede Maik, Neumann Jörg, Kracht Dietmar
Laser Zentrum Hannover eV, Hannover, Germany.
Opt Express. 2010 Sep 13;18(19):20461-74. doi: 10.1364/OE.18.020461.
The output power of linearly polarized Nd:YAG lasers is typically limited by thermally induced birefringence, which causes depolarization. However, this effect can be reduced either by use of some kind of depolarization compensation or by use of crystals which are cut in [110]- and [100]-direction, instead of the common [111]-direction. Investigations of the intrinsic reduction of the depolarization by use of these crystals are presented. To our knowledge, this is the first probe beam-experiment describing a comparison between [100]-, [110]- and [111]-cut Nd:YAG crystals in a pump power regime between 100 and 200 W. It is demonstrated that the depolarization can be reduced by a factor of 6 in [100]-cut crystals. The simulations reveal that a reduction of depolarization by use of a [110]-cut crystal in comparison with a [100]-cut crystal only becomes possible at pump powers in the kW region. Analysis also shows that the bifocusing for [100]-cut is slightly smaller and more asymmetrical than for [111]-cut.
线性偏振钕钇铝石榴石激光器的输出功率通常受热致双折射限制，热致双折射会导致去极化。然而，可通过使用某种去极化补偿或使用沿[110]和[100]方向切割而非常见的[111]方向切割的晶体来降低这种效应。本文介绍了利用这些晶体对去极化固有降低情况的研究。据我们所知，这是首次在100至200瓦泵浦功率范围内对[100]、[110]和[111]切割的钕钇铝石榴石晶体进行比较的探测光束实验。结果表明，[100]切割的晶体中去极化可降低6倍。模拟结果显示，与[100]切割的晶体相比，仅在千瓦级泵浦功率下，使用[110]切割的晶体才有可能降低去极化。分析还表明，[100]切割的双聚焦比[111]切割的略小且更不对称。
