Next Generation of Ceramic Laser

本课题的研究目的是为陶瓷激光器的发展指明新的方向。（1）高透明陶瓷材料的晶界控制研究：为了设计高透明陶瓷材料的光谱特性，我们研制了无序Nd：Y_3Sc_XAl_（5-X）&gt;O_<12>和Yb：Y_3Sc_XAl_（5-X）&gt;O_<12>。另外，通过Nd：Y_3Al_5O_2<12>和Nd：Y_3Sc_XAl_&lt;（5-X）&gt; O_2的组合<12>，增加了新的功能。（2）光谱分析与激光器设计研究：对激光陶瓷的光谱特性进行了表征，建立了激光器设计准则。（3）波长扩展：为了克服激光波长的限制，我们发展了一种新的场极化方法制备周期极化掺MgO的LiNbO_3（PPMgLN）。通过使用5毫米厚和36毫米长的PPMgLN，我们已经成功地在100 mJ和70%的光学参量振荡。（4）热带激光上能级直接泵浦：我们证明了将激光上能级直接泵浦应用于这些陶瓷激光器，量子缺陷得到改善。（5）高亮度微片陶瓷激光器的研制：利用Yb：Y_3Sc_XAl_（5-X）&gt;O_<12>3，我们实现了280 fs超快脉冲的产生，这是我们所知的世界纪录。另外，在Yb：YAG单晶和YAG陶瓷复合结构，对应57 kW/cm^3输出功率密度。本年度发表评论论文30余篇，国际会议邀请论文7篇等，并获得“2004年度文部大臣表彰”。日本科学技术奖（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".