Next Generation of Ceramic Laser

我们的研究目的是为陶瓷激光器开辟新的发展方向。特别是，为改进激光系统，我们尝试了如下控制晶粒和畴边界的功能光学器件；(1)高透明陶瓷材料的晶界控制研究：为了设计光谱特性，我们开发了无序Nd: Y_3Sc_XAl_<(5-X)>O_<12>和Yb: Y_3Sc_XAl_<(5-X)>O_<12>。此外，通过组合Nd: Y_3Al_5O_<12>和Nd: Y_3Sc_XAl_<(5-X)>O_<12>，我们添加了新的函数。(2)光谱分析和激光设计研究：为了建立设计标准，我们对这些激光陶瓷的光谱特性进行了表征。(3)波长扩展：为了克服激光波长的限制，我们开发了一种新的周期性极化MgO材料LiNbO_3 （PPMgLN）的场极化制备方法。利用厚度为5 mm、长度为36 mm的PPMgLN，我们成功地实现了100-mJ和70%的光学参量振荡。(4)热带激光上能级直接泵浦：我们已经证明了将激光上能级直接泵浦应用于这些陶瓷激光器可以改善量子缺陷。(5)高亮度微芯片陶瓷激光器的研制：利用Yb: Y_3Sc_XAl_<(5- x)>O_<12>，实现了280fs的超快脉冲产生，创造了目前所知的世界纪录。另外，Yb: YAG单晶和YAG陶瓷复合结构的连续输出功率为340 W，对应的输出功率密度为57 kW/cm^3。今年共发表评审论文30余篇，国际会议特邀论文7篇等。此外，我们还获得了“2004年日本文部科学大臣表彰（科学技术研究功勋人物）”和“日本激光学会先进研究奖奖章”。

The aim of our research is to clear the new direction of ceramic laser. Especially, to create the functional optical devices for improved laser system, we have tried to control the grain and domain boundary as following ;(1)Research of grain boundary control for the high-transparent ceramic material : To design the spectral property, we have developed disordered Nd : Y_3Sc_XAl_<(5-X)>O_<12> and Yb : Y_3Sc_XAl_<(5-X)>O_<12>. Additionally, by combining Nd : Y_3Al_5O_<12> and Nd : Y_3Sc_XAl_<(5-X)>O_<12>, we have add the new function.(2)Research of spectroscopic analysis and laser design : To establish the design criteria, we have characterized the spectroscopic property of these laser ceramics.(3)Wavelength extension : To overcome the limited lasing wavelength, we have developed the fabrication method of new field poling method for periodically poled MgO deoped LiNbO_3 (PPMgLN). By using 5-mm thickness and 36-mm long PPMgLN, we have succeeded in 100-mJ and 70% optical parametric oscillation.(4)Hot band laser upper level direct pumping : We have demonstrated the quantum defect improvement by applying the laser upper level direct pumping to these ceramic lasers.(5)Development of the high brightness microchip ceramic laser : By using Yb : Y_3Sc_XAl_<(5-X)>O_<12>, we have demonstrated the ultrafast pulse generation of 280fs, which is the world record in our knowledge. Otherwise, CW output power of 340 W has been obtained in the Yb : YAG single crystal and YAG ceramics composite structure, which corresponded to 57 kW/cm^3 output power density.This year, we have published over 30 reviewed papers, 7 invited papers of international conference, and so on. Moreover, we have received "2004 Commendation by the Minister of Education, Culture, Sports, Science and Technology of Japan (Person of Scientific and Technological Research Merits) " and "Medal for Advanced Research Award, The Laser Society of Japan".