Passively Q-switched diode-pumped Nd:YAG and Nd:YVO₄ using (Cr⁴⁺,Ca²⁺):YAG and (Cr⁴⁺,Mg²⁺):YAG saturable absorbers

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• 作者：Yehoshua Kalisky ; Ofra Kalisky ; Milan R. Kokta
• 关键词：Diode-pumped lasers ; Saturable absorber ; Nd-doped vanadate lasers ; Nd ; YAG
• 刊名：Optical Materials
• 出版年：2008
• 出版时间：July 2008
• 年：2008
• 卷：30
• 期：11
• 页码：1775-1780
• 全文大小：157 K

文摘

We report the operation of passively Q-switched diode-end-pumped Nd:YAG and Nd:YVO₄ lasers by employing Cr⁴⁺-doped garnets with Ca²⁺ or Mg²⁺ as charge compensators. We found that the laser performance improved significantly, mainly in the Nd:YVO₄ system when (Cr⁴⁺,Mg²⁺):YAG sample was used as a passive Q-switching. For example, in the Nd:YVO₄ and Nd:YAG lasers, the maximum peak power using (Cr⁴⁺,Mg²⁺):YAG saturable absorber was higher by a factor of 8.5 and 2.6, respectively, relative to (Cr⁴⁺,Ca²⁺):YAG. This fact is attributed to better optical quality of the (Cr⁴⁺,Mg²⁺):YAG sample, as a result of improved dopant distribution and reduced internal stresses inside the saturable absorber crystals. Similar passively Q-switched laser performance can be obtained by using other garnets with an open structure, and hence, with low internal stresses, such as (Cr⁴⁺,Ca²⁺):GGG. We also compared the laser performance of Nd:GdVO₄ with the same saturable absorbers and obtained both passive Q-switching and passive mode locking. By using an analytical model with the relevant physical parameters of the laser crystals and saturable absorbers it is possible to optimize the laser performance.