Er掺杂GaSe晶体特性的研究

Study on the properties of Er doped GaSe crystals

对改进型布里奇曼方法生长的Er掺杂GaSe晶体的成分、光学特性和倍频特性进行了测量和分析。研究发现,掺杂晶体中Er的分布不均匀且浓度远低于装料浓度,高浓度掺杂使得晶体光学质量下降。通过对掺杂晶体光学特性测量发现,Er的掺杂没有明显改变晶体的光谱特性,掺杂浓度为0.07mass.%的GaSe:Er晶体在可见光波段表现出了比较好的光学性质。通过对晶体拉曼光谱的测量发现,在GaSe:Er(0.09mass.%)和GaSe:Er(0.10mass.%)晶体中出现了新的拉曼散射带,它是由Er3+的4F9/2→4I9/2跃迁产生的。通过飞秒Ti:sapphire激光和CO2激光泵浦下I类倍频实验发现,掺杂晶体相位匹配角与纯GaSe晶体相比没有明显变化,实验结果与理论曲线符合得较好,最佳浓度掺杂晶体GaSe:Er(0.07 mass.%)将CO2倍频转换效率提高了43%。

The composition,optical and second harmonic properties of Er doped GaSe crystals grown by modified Bridgman technology are investigated.It is found that Er content is not uniform in the grown crystals and much lower than that in the melt compositions.Higher Er doping level makes the optical quality decrease.The spectrum property doesn′t change obviously with Er doping,but the crystal whose Er content equals to 0.07%in mass shows better optical properties in visible region than other crystals.New Raman scattering bands are found in GaSe：Er（0.09%in mass）and GaSe：Er（0.10%in mass）crystals,which are attributed to 4F9/2→4I9/2transitions in Er3＋ions through the Raman spectrum measurement.No obvious differences of type I second harmonic phase matching angle between pure and Er doped crystals are found with femtosecond Ti：sapphire laser and CO2 laser pumping.The experimental results are in good agreement with the theoretical curves.The second harmonic generation efficiency under CO2 laser pumping is increased by 43%in the optimal doped crystal GaSe：Er（0.07%in mass）among all used samples.The results in this paper may provide reference for the application of GaSe：Er crystals in nonlinear optics and also the research of some other relative doping crystals.