Study of New Borate Crystal for Ultraviolet Light Generation

本研究的结果总结如下：我们从2800 mJ的输入得到266 nm和213 nm的输出，脉冲能量分别为600 mJ和320 mJ。据我所知，这些是有史以来通过纳秒脉冲Nd: YAG激光的NLO频率转换产生的最高紫外激光能量。在这项工作中没有应用晶体温度控制。观察到良好的输出稳定性和圆形光束模式。利用CLBO晶体实现了大功率全固态紫外激光器。研究了掺杂对各种性能的影响。发现Rb掺杂可以缩短CLBO的SHG截止波长（lc），例如在10 mol % Rb掺杂（Rs/Cd=0.1）的熔体中生长的晶体lc缩短了2 nm。然而，Rb兴奋剂使CLBO更加脆弱。K和Na的掺杂也是如此。另一方面，Al的掺入可以提高CLBO的力学性能。熔体中Al/Cs比的维氏硬度函数。每个数据点表示从每个样本的若干缩进中获得的平均值。未掺杂CLBO的（100）和（001）表面硬度分别为270和180，掺1% al和5% al的CLBO（100）表面硬度分别为290和310，掺5% al的CLBO（001）表面硬度分别为220和230。实际上，掺杂al的CLBO晶体即使在多晶状态下也不会出现裂纹。结果表明，Al的掺入使CLBO的吸湿性降低。将未掺杂和掺2%Al的CLBO晶体分别溶解在h2o（20%）和甘油（80%）的溶液中，考察掺杂对CLBO晶体抗水性能的影响。在实验过程中，样品已浸在溶液中。实验表明，掺铝的CLBO比未掺铝的CLBO具有更低的可溶性。

The results obtained in this research are summarized as followings.We have obtained 266 nm and 213 nm output with a pulse energy of 600 mJ and 320 mJ,respectively, from the input of 2800 mJ.To the best of my knowledge, these have been the highest ever generated UV laser energy through NLO frequency conversion of nanoseconds pulsed Nd : YAG laser. There were no crystal temperature control applied in this work. Excellent output stability and rounded beam pattern were observed. High power all solid state UV laser via CLBO crystal is realized.Effect of doping on the various properties has been studied. It was found that Rb doping could shorten CLBO's SHG cutoff wavelength (lc), for example the lc became 2 nm shorter for the crystal grown from 10 mole % Rb-doped (Rs/Cd=0.1) melt. The Rb doping, however, has made CLBO more fragile. This was also the case for the K and Na doping. On the other hand, the Al doping could give rise to an enhancement of mechanical properties of CLBO.The Vickers hardness as a function of the Al/Cs ratio in the melt. Each data point represents an average value obtained from a number of indents on each sample. The hardness of undoped CLBO was 270 and 180 for (100) and (001) surfaces, respectively, while values for 1% Al-doped and 5% Al-doped CLBO were 290 and 310 for (100) and 220 and 230 for (001) surfaces. Actually, the Al-doped CLBO crystals have not been cracked even when they were the polycrystalline.It was found that the hygroscopic nature of CLBO become less by the Al doping. The undoped and 2%Al doped CLBO crystals were dissoved in the solution of H_2O (20%) and glycerin (80%) in order to investigate the effect of doping on resistance against water. The samples have been dipped in the solution during experiment. This experiment has shown that the Al-doped CLBO is less soluble than undoped CLBO.