2.8-3微米Yb3+单掺或Cr3+,Yb3+双掺敏化的Ho3+:YAlO3激光晶体生长及性能研究

YAlO3 (YAP) is an excellent matrix crystal, the 2.8-3 micrometer wavelength polarization laser can be realized in the Ho:YAP crystal,which has important applications in the medicine, scientific and military fields. However, the single doped Ho3+ laser crystal cannot be pumped by LD pumping source and flash lamp. Our early spectra experiments indicate tnat Yb,Ho:YAP with Ho3+ ions sensitized by Yb3+ ions, which is suitable to be pumped by the 940nm or 970nm LD; the Cr,Yb,Ho:YAP with Ho3+ sensitized by double-doped Cr3+, Yb3+ ions, which is suitable to be pumped by flash lamp. At last, 2.8-3 μm polarization laser can be generated between the energy levels transition of 5I6 and 5I7 of Ho3+ ions. The experiment also suggests that the long laser lower level(5I7) lifetime of Ho3+ can be decreased by energy level coupling.In this project, we will grow the crystals with high optic quality by Czochralski method, to decrease the lifetime of laser low level by energy level coupling, to reduce the thermal lens effect by high temperature thermal-bonding for the purpose of the improvement of laser performance. In further, to optimize the doping concentration of sensitization,activation and energy coupling ions,to obtain the Ho:YAP crystal with high porformance,so that establish a foundation for the application of 2.9 micrometer Ho3+ laser。

YAlO3(YAP)是优良的激光基质晶体，掺Ho3+的YAP晶体可以实现2.8-3微米的偏振调谐激光输出，在医疗、科研及军事等领域有着重要的应用前景。然而单掺Ho3+的晶体尚不能直接用目前LD泵浦源或闪光灯泵浦。我们初步的光谱实验表明，采用Yb3+敏化的Yb,Ho:YAP，适合940nm或970nm LD泵浦;采用Cr3+,Yb3+共掺敏化的Cr,Yb,Ho:YAP，适合闪光灯泵浦，两种晶体最后都要通过Ho3+离子5I6和5I7两个能级之间的跃迁，实现2.8-3μm调谐的偏振激光输出。初步的实验表明,通过能级耦合,可改善Ho3+激光下能级5I7寿命过长的问题。本项目将采用提拉法生长高光学质量晶体，通过能级耦合降低激光下能级寿命，采用热键合复合晶体减小热透镜效应，提高激光性能，通过优化敏化、激活及能级耦合离子浓度，获得高性能的Ho:YAP激光晶体,为2.9微米附近波长的激光应用奠定基础。

YAlO3(YAP)是优良的激光基质晶体，掺Ho3+的YAP晶体可以实现2.8-3微米的偏振调谐激光输出，在医疗、科研及军事等领域有着重要的应用前景。然而单掺Ho3+的晶体尚不能直接用目前LD泵浦源或闪光灯泵浦。本项目中，我们提出采用Yb3+单掺敏化或Cr3+,Yb3+双掺敏化的方法使晶体分别适合970nm LD或闪光灯泵浦。按照四年研究计划开展了晶体设计、生长及退火等工作，生长出了纯YAP及多种掺杂的晶体，如Ho:YAP、Yb,Ho:YAP、Yb,Ho,Pr:YAP、Cr,Yb,Ho:YAP、Cr,Yb,Ho,Eu:YAP及Cr,Yb,Ho,Pr:YAP等，对晶体的吸收光谱、光谱参数计算、荧光光谱、能级寿命及能量转移机理、热学特性、晶体微观缺陷等进行了研究，并通过掺入能级耦合离子Pr3+或Eu3+的退激活方法进一步减小Ho3+的下能级寿命，采用闪光灯泵浦获得了2.84μm中红外激光输出。因此通过敏化与能级耦合的Ho:YAP系列晶体是一种优良的中红外激光晶体材料，在上下能级寿命优化及激光性能提高等方面值得进一步深入研究。