激光浮区法生长TbYO_(3)晶体

Growth of TbYO_(3)Crystal by Laser Floating Zone Method

随着高功率固态激光器和光纤激光器的发展,对可见光-近红外区域的光学隔离器要求逐渐增加。目前设备原件正趋于小型化发展,工业应用最广泛的铽镓石榴石(TGG)晶体因其较小的Verdet常数,无法满足未来高功率激光器的需要。Tb 2 O_(3)具有较高的Verdet常数,但是高熔点和相变机制使其难以通过常规提拉法进行单晶生长。本研究通过向Tb_(2)O_(3)中掺杂Y_(2)O_(3),研究了不同掺杂浓度下(Tb x Y 1-x)2 O_(3)的晶体生长。在n(Tb)∶n(Y)=1∶1时,通过激光浮区(LFZ)法生长了TbYO_(3)单晶,而纯净的Tb_(2)O_(3)和(Tb 0.3 Y 0.7)_(2)O_(3)单晶无法通过该方法合成。TbYO_(3)晶体具有较高的Verdet常数(445 nm处为529 rad·T^(-1)·m^(-1),880 nm处为116 rad·T^(-1)·m^(-1)),为TGG晶体(445 nm处为350 rad·T^(-1)·m^(-1),880 nm处为49 rad·T^(-1)·m^(-1))的1.51~2.37倍。因此,TbYO_(3)晶体可以有效减少构建光学隔离器的介质长度或降低嵌入光学隔离器所需的磁场强度。此外,TbYO_(3)晶体还具有11 W·m^(-1)·K^(-1)的中等热导率,1.67 GW·cm-2的高激光损伤阈值。这些优点可以使TbYO_(3)晶体成为一种有吸引力的磁光材料。

With the development of high-power solid-state lasers and fiber lasers,the demand for optical isolators in the visible and near-infrared regions is gradually increasing.At present,equipment components are tending towards miniaturization.The most widely used terbium gallium garnet(TGG)crystal in industry cannot meet the needs of future high-power lasers due to its small Verdet constant.Tb_(2)O_(3)has a high Verdet constant,but its high melting point and phase transition mechanism make it difficult to achieve single crystals by Czochralski.The crystal growth of(Tb x Y 1-x)2 O_(3)at different doping concentrations was explored by doping Y_(2)O_(3)into Tb_(2)O_(3)in this study.When the ratio of n(Tb)∶n(Y)was 1∶1,TbYO_(3)single crystals were grown by laser floating zone(LFZ)method,while undoped Tb_(2)O_(3)and(Tb 0.3 Y 0.7)2 O_(3)single crystals cannot be synthesized by this method.The TbYO_(3)crystal has high Verdet constants(529 rad·T^(-1)·m^(-1)at 445 nm and 116 rad·T^(-1)·m^(-1)at 880 nm),which is 1.51 to 2.37 times that of terbium gallium garnet(TGG)crystal(350 rad·T^(-1)·m^(-1)at 445 nm and 49 rad·T^(-1)·m^(-1)at 880 nm).Therefore,the TbYO_(3)crystal can effectively reduce the medium length for constructing optical isolators or decrease the magnetic field intensity required for embedding optical isolators.In addition,TbYO_(3)crystal also has a moderate thermal conductivity of 11 W·m^(-1)·K^(-1)and a high laser induced damage threshold of 1.67 GW·cm-2.These advantages make TbYO_(3)crystal an attractive magneto-optical material.