新型高费尔德常数法拉第磁旋光透明陶瓷制备研究

High power laser system requires new Faraday magneto-optical materials with large Verdet constant, high thermal conductivity, and large size preparation. Terbium aluminum garnet (TAG) has excellent performance, however, the size of the obtainable TAG crystal is too small to be used due to its incongruent melting characteristics,therefore terbium gallium garnet (TGG) crystal is employed practically instead of TAG although its Verdet constant is about 38% smaller than that of TAG. We synthesized the TAG magneto-optical transparent ceramics with almost the same properties as TAG crystal for the first time in 2011, and its superiority has been confiremed by the Russian Academy of Science according to the high energy laser experiment using the TAG samples supplied by our group in 2013, therefore the application prospect of TAG transparent ceramics attracts great attention in the world, and it has be reported by several papers published in OPTICS LETTERS and OPTICS EXPRESS in 2014. This project plans to carry out the systematical research on the high-quality preparation and the magneto-optical propeties of the TAG　transparent ceramics. The mechanism of the enhancement of Verdet constant will be investigated, the effect of the additive and doping will be studied on the extinction ratio, scattering,thermal distortion, optical homogeneity and laser damage. Effort will be made to low optical loss, improve the optical homogeneity and promote its application in high power laser system.

高能激光系统需要费尔德常数大、热导率高、并且能大尺寸制备的新型法拉第磁旋光材料。铽铝石榴石（TAG）性能优越，但由于其非一致熔融特性，实用大小的TAG晶体一直无法获得，目前广泛使用的是费尔德常数比TAG小约38%的铽镓石榴石（TGG）晶体。2011年我们在国际上首次做出了TAG法拉第磁旋光透明陶瓷，其性能指标几乎与TAG晶体完全一致，2013年俄罗斯科学院对我们提供的TAG透明陶瓷进行了高能激光试验，其应用前景受到国际关注，2014年在OL和OE上已有多篇论文进行报道。本项目拟系统研究TAG法拉第磁旋光透明陶瓷的高质量制备与磁光性能，研究磁旋光系数增大机理，研究添加剂以及掺杂对消光比、散射、热畸变、光学均匀性、激光损伤等材料性能的影响，降低光损耗，提高光学均匀性，推动其在大功率激光系统上应用。

强激光系统需要激光损伤阈值高，费尔德常数大、热导率高、并且能大尺寸制备的新型法拉第磁旋光材料。铽铝石榴石（TAG）性能优越，但由于其非一致熔融特性，实用大小的TAG晶体一直无法获得，目前广泛使用的是费尔德常数比TAG小约38%的铽镓石榴石（TGG）晶体。..本项目主要研究了TAG法拉第磁旋光透明陶瓷的高质量制备与磁光性能,并获得了以下重要结果：..（1）通过使用ZrO2添加剂，获得了高光学质量的Zr:TAG的透明陶瓷，其在1064nm附近的透过率接近理论通过率，达到82.04% 。..（2）首次对所制备的Zr：TAG透明陶瓷进行了激光损伤阈值测定， 结果为7.26J/cm2 @12 ns，这个数值比文献报道的TGG晶体的激光损伤阈值要高。..（3）制备了Ce-TAG，得到较高光学质量的Ce-TAG透明陶瓷。..（4）观察到晶粒异常长大但光学散射反而减小的实验现象。晶粒大小可大到数百微米（400–500 μm），但光学透过率却更高。这种晶粒异常长大发生在生长后期气孔或空腔完全排除的情况下，晶粒长大导致晶界减少，从而散射下降。..(5)制备了Si掺杂TAG，得到较高光学质量的Si-TAG。比较了多种掺杂对费尔德常数的影响，发现Ti、Si、Ce掺杂都可以显著提高TAG的费尔德常数。TAG的热退偏要好于TGG，并且在TAG的诸多掺杂中，0.2at%Si-TAG的热退偏性能较好。..(6) 测试了Ti掺杂TAG样品的变温费尔德常数，丰富了对TAG磁旋光系数的温度特性的认识。