近化学计量比LiNbO_3晶体光学性能的研究

Study on Optical Properties of Near-stoichiometric LiNbO_3 Crystal

采用助溶剂法和Li/Nb比改变法以Czochralski技术生长近化学计量比LiNbO3晶体(SLN)。测试晶体的吸收光谱,SLN的吸收边位于313nm,比同成分LiNbO3晶体(CLN)紫移9nm。测试晶体的红外光谱,SLN的OH-吸收峰有2个,分别位于3466cm-1和3480cm-1。以Ar+激光器波长λ=514.5nm作光源测得化学计量比LiNbO3指数增益系数Γ为25cm-1,同成分LiNbO3晶体的指数增益系数为9cm-1。

Near-stoichiometric LiNbO_3 crystal (SLN) were grown by the Czochralski method from K_2O-doped melts and Li-rich melts. The absorption spectra, infrared transmission spectra and exponential gain coefficient of the crystals were measured. The absorption edge of SLN was at 313 nm,which shifted to violet band for 9 nm compared with congruent LiNbO_3 crystal(CLN). Two OH?absorption peaks located at 3 466 cm^(-1) and 3 480 cm^(-1) were observed in the SLN. The value of exponential gain coefficient of SLN was 25 cm^(-1),about three times larger than that of CLN(9 cm^(-1)).