Liu Jun-Hai

Anisotropy of Nonlinear-Optical Property of RCOB ( R = Gd, Y) Crystal

The nonlinear-optical coefficients of RCOB (R = Gd, Y) crystals are measured. The spatial distribution of deff (effective nonlinear-optical coefficient) is subsequently determined. Our experiments show that the maximum deff occurs at the second quadrant. The second-harmonic generation efficiency reaches 48% for a 6 mm long, (113.2°, 47.4°)-cut GdCOB, and 41.5% for a 5mm long, (113°, 36.5°)-cut YCOB, respectively. The intracavity frequency doubling of GdCOB is reported for the first time.

Thermal Lensing Measurement and Laser Performance of End-Pumped Lightly Doped Nd:GdVO4 Crystal

The thermal lensing effect generated in an end-pumped lightly doped Nd:GdVO4 crystal was found to be considerably weaker than that in Nd:YVO4 having the same Nd3+ concentration. Consequently, the laser performance of Nd:GdVO4 at high pump powers over 20 W was found to be superior to that of Nd:YVO4. TEM00 mode cw radiation of 14.3 W at 1.06 μm was achieved with an optical conversion efficiency of 55%, and average slope efficiency of 62%.

Growth and Second-Harmonic Generation Properties of Tm3+, Yb3+, Bi3+ and Li+ Doped GdCa4O(BO3)3 Crystals

The rare-earth ions (Yb3+, Tm3+) and Li+, Bi3+ ions doped GdCa4O(BO3)3 crystals were grown using the Czochralski pulling method. The second-harmonic generation conversion efficiencies of the GdCOB:Yb and GdCOB:Tm crystals are 31.3% and 33.3%, respectively, while the undoped GdCOB crystal is 27.9%. The conversion efficiencies of Yb3+, Tm3+ doped GdCOB are improved by 12% and 19%, respectively, compared to that of the undoped one. The conversion efficiencies of Li+, Bi3+ doped GdCOB crystals are 33% and 38.3%, which are improved by 15% and 37% as compared to that of the undoped crystal. The results are discussed using the anion group theory.

Effect of Strontium Ion on the Growth and Second-Harmonic Generation Properties of GdCa4O(BO3)3 Crystal

Large sized and optical quality GdCa4O(BO3)3 (GdCOB) crystal with calcium partially substituted by strontium (Sr) ions was grown for the first time. The x-ray powder diffraction shows that the Sr ion has an effect on the cell parameters of the GdCOB crystal. Second-harmonic generation (SHG) experiments were performed on the Sr:GdCOB and GdCOB crystals along the spatial phase-matching direction. The results show that the cw green laser output power is 1.04 W when the laser diode pump power is 10 W in the Nd:YVO4/Sr:GdCOB intracavity laser. Considering the slope efficiency of Nd:YVO4 and the fundamental laser in cavity, the intracavity SHG conversion efficiency of the GdCOB crystal is 21% while it is 24% for the Sr:GdCOB crystal, the SHG conversion efficiency is improved by 14%. The effect of the Sr ions on the nonlinearity of the GdCOB crystal is also discussed by using the anion group theory. PACS: 42. 65. Ky, 78. 20. -e, 78. 55. Hx