Nd~(3+):LiNbO_3晶体的坩埚下降法生长及光谱特性

以同成分化学组分比(Li2O:48.6mol%,Nb2O5:51.4mol%)为原料,Nd2O3为掺杂剂,应用坩埚下降法技术,生长了Nd3+初始掺杂为0.2mol%的LiNbO3晶体。测定了晶体的差热曲线、红外吸收光谱、紫外-可见吸收光谱,并与用提拉法技术生长的晶体性质进行了比较。观测到了Nd3+的特征吸收峰。在800nm的半导体激光激发下研究了晶体在1.06μm附近的荧光曲线和荧光寿命,观测到了1067,1080,1085,1093,1106nm五个分裂的4F3/2→4I11/2能级跃迁发射峰。测定了最强荧光峰(1085nm)的荧光寿命为351μs。与用提拉法技术生长的晶体相比,其荧光寿命得到了大幅度的变长,约为3.5倍。在密封条件下用坩埚下降法技术生长的晶体,由于在生长过程中隔绝了空气和水汽,所以在获得的晶体中具有低的OH-离子浓度,获得了长的荧光寿命。

Growth and optical spectra of Nd3+:LiNbO3 crystals grown by Bridgman method

The growth of LiNbO_3 crystals doped with Nd~(3+)in 0.2 mol% concentration in raw materials by Bridgman method in congruent composition(Li 2O:48.6mol%,Nb 2O 5:51.4mol%)and Nd 2O 3 as dopant is reported.The DTA curve and infrared absorption spectra of the crystal are measured and compared with those of crystal grown by Czochralski method,and the ultraviolet-visible absorption spectrum,fluorescence spectra and the curve of fluorescence decay at 1.06 μm are also recorded.The five split absorption peaks at 1067,1080,1085,1093,1106nm of 4F 3/2 → 4I 11/2 are observed.The lifetime of 4F 3/2-4I 11/2 is 351μs which is about 3.5 times as those grown by Czochralski method.The crystal grown by Bridgman method under the condition of closed crucible,which can prevent the crystal from the air and water in the growing processing,possesses low OH-concentration,the long lifetime of the emission light is obtained.