CHARACTERIZATION OF VISIBLE,TUNABLE SOLID STATE LASER MATERIALS

用晶体中的过渡金属离子Cr^&lt；3+&gt；，Ti^-lt；3+&gt；和稀土离子Ce^&lt；3+&gt；由于它们的基态电子和激发态电子的电子-声子耦合有很大的不同，光学跃迁具有宽的吸收和发射带，导致了宽的激光振荡调谐范围。最近，我们报道了在室温下从Cr^&lt；3+&gt；：LiCaAlF_6，Ti^&lt；3+&gt；：Al_2O_3和Ce^&lt；3+&gt；：LiYF_4晶体中获得的光泵浦固体可调谐激光器。为了获得新型可调谐固体激光材料，我们用电子自旋共振(ESR)和光谱方法研究了Cr^&lt；3+&gt；，Ti^&lt；3+&gt；，Ce^&lt；3+&gt；：CaYAlO4(CyA)的电子性质。吸收带的偏振强度和R_1线的荧光表明，CrO_6^&lt；9-&gt；八面体发生了角变形，使得光谱的磁性z轴偏离晶体c轴，得到Ce^&lt；3+&gt；在CyA中的g张量为g_&lt；11&gt；=2.6，g_*=1.6。ESR结果表明，CyA中Ce^&lt；3+&gt；的基态波函数的主要分量为|J，J_Z&gt；=|5/2，5/2&gt；Ce~(2+)~(3+)和Gt~(3+)在紫外区(200-370 nm)有吸收，在490 nm处有一个发光峰。

Transition metal ions Cr^<3+>, Ti^<3+> and rare earth ions Ce^<3+> in crystals are used as laser active ions. Since electron-phonon couplings of their ground and excited state electrons are quite different, the optical transitions feature broad absorption and emission bands, giving rise to a wide tuning range of laser oscillation. Recently, the demonstrations of optically pumped solid-state tunable lasers obtained from Cr^<3+> : LiCaAlF_6, Ti^<3+> : Al_2O_3, and Ce^<3+> : LiYF_4 crystals at room temperature were reported. In order to obtain new tunable solid state laser materials, we have examined the electronic properties of Cr^<3+>, Ti^<3+>, Ce^<3+> : CaYAlO_4 (CYA) using electron spin resonance (ESR) and optical spectroscopy.ESR studies of Cr^<3+> in CYA show Cr^<3+> ions in sites with ordered and disordered configurations of the second nearest-neighbor Ca^<2+>/Y^<3+> ions, respectively. The polarized intensities of the ^4A_2-^4T_2 absorption band and the R_1-line fluorescence suggest that the CrO_6^<9-> octahedra undergo an angular distortion such that the magnetic z-axis of the spectrum is rotated away from the crystal c-axis.The g tensor of Ce^<3+> in CYA was obtained to be g_<11>=2.6, g_*=1.6. The ESR results indicate that the wavefunction of the ground state of Ce^<3+> in CYA has a dominant component of |J,J_Z>=|5/2,5/2>. The absorption of Ce^<3+> in CYA was observed in the UV region (200-370nm) and the luminescence band has a peak at 490nm.