掺铬锗酸锂可调谐激光晶体研究

Study on the Chromium-doped Lithium GermanateTunable Laser Crystal

利用提拉法缓冷工艺，生长出掺Ｃｒ３＋／离子的Ｌｉ２ＧｅＯ３晶体，按Ｔａｎａｂｅ－Ｓｕｇａｎｏ能级图和吸收光谱，计算出Ｃｒ３＋在Ｌｉ２ＧｅＯ３晶体场中的光谱参数（Ｒａｃａｃｈ参数）为Ｂ＝５７３ｃｍ－１，Ｃ＝２２９２ｃｍ－１，Ｄｑ／Ｂ＝２３．八面晶场分裂参数：ｏ＝１２７７９ｃｍ－１，在红外和近红外区激发Ｌｉ２ＧｅＯ３：Ｃｒ３＋晶体，在７９６．２ｎｍ，９３２．９ｎｍ和９６２．５ｎｍ处观测到有红外宽带发射．通过分析２５０ｎｍ激发的荧光光谱，判断晶体中可能有Ｃｒ４＋占据八面体心或八面体空位而引起在４０８．５ｎｍ处的可见发射．

The Cr3+-doped Li2GeO3 crystal was grown by the Czochraski technique.The spectrum parameters of Cr3+. ions, Racah Coefficient, in Li2GeO3 crystal field were worked out: B=573 cm-1, C=229 2 cm -1 Dq/B=2.23, 0=12779 cm-1 and the split cofficient of octahed crystal field according to Tanabe-Sugano energy level diagram and the absorption spectra. The wide infrared emission bands in 796.2 nm, 932.9 nm and 962.5 nm region were observed. The visible emission excited with 250 nm light beam in 408.5 nm may be produced by Cr4+ in octahedral center.