新型激光自倍频晶体Cr:Nd:Gd Ca_4O(BO_3)_3

New Laser Self frequency doubling Crystal Cr:Nd:Gd Ca_ 4O(BO_3)_3

首次利用提拉法生长了优质铬离子敏化激光自倍频晶体Ｃｒ∶Ｎｄ∶ＧｄＣａ４Ｏ（ＢＯ３）３（Ｃｒ∶Ｎｄ∶ＧｄＣＯＢ） ，发现当铬离子和钕离子双掺时，由于协同效应使铬离子容易进入ＧｄＣＯＢ晶体中，测量了Ｃｒ∶Ｎｄ∶ＧｄＣＯＢ 和Ｎｄ∶ＧｄＣＯＢ晶体的室温透过谱和荧光谱。Ｃｒ∶Ｎｄ∶ＧｄＣＯＢ晶体在蓝紫外区比Ｎｄ∶ＧｄＣＯＢ晶体具有更强的吸收，适合于利用闪光灯泵浦。利用闪光灯泵浦分别对长度为７ｍｍ ，沿最佳倍频方向（θ＝ ６６．８°，＝１３２．６°） 切割的Ｃｒ∶Ｎｄ∶ＧｄＣＯＢ和Ｎｄ∶ＧｄＣＯＢ 晶体进行自倍频实验。Ｃｒ∶Ｎｄ∶ＧｄＣＯＢ的激发阈值为０．９Ｊ，而Ｎｄ∶ＧｄＣＯＢ的激发阈值为１ ．０Ｊ。在１０Ｊ的输入能量时，Ｃｒ∶Ｎｄ∶ＧｄＣＯＢ输出绿光能量为２ ．４６ｍＪ，而Ｎｄ∶ＧｄＣＯＢ输出绿光能量为１ ．９６ｍＪ，说明在该晶体中，铬离子对钕离子有很好的敏化作用。

Chromium ion sensitizing laser self frequency doubling (SFD) crystal of Cr∶Nd∶GdCa 4O(BO 3) 3(Cr∶Nd∶GdCOB) was grown by CZ method,for the first time to our knowledge.The Chromium ion is easy to enter into the lattice of GdCOB crystal because of the co operative effect.The transmittance spectra and fluorescent spectra of Cr∶Nd∶GdCOB and Nd∶GdCOB crystals were measured at room temperature.The absorption in the blue UV region of Cr∶Nd∶GdCOB was larger than that of Nd∶GdCOB,which match with the xenon flash lamp very well.The SFD experiments were performed by flash pump source on 3mm×3mm×7mm Nd∶GdCOB and Cr∶Nd∶GdCOB samples which were cut along the optimum second harmonic generation direction ( θ =66.8°,  =132.6°).The lasing threshold of Cr∶Nd∶GdCOB is 0.9J while Nd∶GdCOB is 1.0J.The output green light energy is 2.46mJ for Cr∶Nd∶GdCOB at 10J flash pump energy and 1.96mJ for Nd∶GdCOB at the same pump energy.The results clearly show that Cr 3+ ions have the sensitizing effect on Nd 3+ ions in GdCOB crystal.