Peng Jing, Liu Xinyao, Wang Jie, Zhang Shaoqing, Xiao Xiao, Xiong Zhengbin, Zhang Kuibao, Chen Baojun, He Zhiyu, Huang Wei
College of Materials Science and Engineering, Sichuan University, Chengdu 610064, China.
State Key Laboratory of Environmentally Friendly Energy Materials, Southwest University of Science and Technology, Mianyang 621010, China.
Inorg Chem. 2023 Jul 31;62(30):12067-12078. doi: 10.1021/acs.inorgchem.3c01582. Epub 2023 Jul 21.
LiAgGaSe is a new series of solid solution crystals that has a large nonlinear optical (NLO) coefficient and laser-induced damage threshold (LIDT). It has great application prospects in mid-infrared laser frequency conversion. In this work, LiAgGaSe ( = 0, 0.2, 0.4, 0.5, 0.6, 0.8, and 1) crystals (Φ 16 mm × 40 mm) were grown by the improved Bridgeman method in a four-zone furnace. It is found that the LiAgGaSe ( = 0.2-0.8) crystals keep the same tetragonal symmetry with AgGaSe and the melting and solidification temperature increase with the Li content. Because the as-grown crystals are almost opaque in the visible-NIR range, an annealing experiment is necessary. After annealing, the transmittance is improved significantly, which can meet the application requirements. The band gap is changed by annealing atmosphere; for instance, the band gap of LiAgGaSe annealed in a LiGaSe powder atmosphere increases from 2.35 to 2.56 eV, while the band gap of LiGaSe annealed in vacuum decreases from 3.39 to 3.01 eV. Finally, the LiAgGaSe shows an extreme SHG response, especially LiAgGaSe, which has about five times that of LiGaSe, proving the promising NLO properties.
LiAgGaSe是一种新型的固溶体晶体，具有大的非线性光学（NLO）系数和激光诱导损伤阈值（LIDT）。它在中红外激光频率转换方面具有广阔的应用前景。在本工作中，采用改进的布里奇曼法在四温区炉中生长了LiAgGaSe（x = 0、0.2、0.4、0.5、0.6、0.8和1）晶体（Φ 16 mm × 40 mm）。发现LiAgGaSe（x = 0.2 - 0.8）晶体与AgGaSe保持相同的四方对称性，且熔化和凝固温度随Li含量的增加而升高。由于生长的晶体在可见 - 近红外范围内几乎不透明，因此需要进行退火实验。退火后，透过率显著提高，可满足应用要求。带隙会因退火气氛而改变；例如，在LiGaSe粉末气氛中退火的LiAgGaSe的带隙从2.35 eV增加到2.56 eV，而在真空中退火的LiGaSe的带隙从3.39 eV降低到3.01 eV。最后，LiAgGaSe表现出极强的倍频（SHG）响应，特别是LiAgGaSe的SHG响应约为LiGaSe的五倍，证明了其有前景的NLO性能。
