Zhang Huaijin

Electrooptic properties and electrooptic Q switch of La3Ga5SiO14 single crystal

The electrooptic coefficients of La3Ga5SiO14 (langasite, LGS) single crystal have been determined. The results obtained are γ11=2.2 pm/V and γ41=1.8 pm/V. With the propagating light along the optical axis and the applied electric field parallel to the x or y axis, LGS single crystal has been configured as a Pockels cell placed in the laser cavity. The Pockels cell successfully acted as an on-off Q switch, and the output power of the YAG laser was 2 J at modulated frequencies of 1, 10 and 20 times/s.

Eye-Safe Raman Laser at 1.5μm Based on BaWO4 Crystal

Using an external couple cavity and a pump beam compression system, efficient 1.5 μm eye-safe Raman laser is obtained based on BaWO4 crystal. The largest output energy is 8.5mJ, corresponding to an electric-optical conversion efficiency of 47%.

Compact diode-pumped continuous-wave Nd : LuVO4 lasers operated at 916 nm and 458 nm

We report the compact diode-pumped continuous-wave (CW) Nd:LuVO4 lasers operated at 916 nm and 458 nm for the first time. The maximum output power of 780 mW at 916 nm laser is obtained with a slope efficiency of 9.3%. We generate 50 mW of 458 nm blue laser employing a type-I critical phase-matched LBO crystal.

Picosecond Stimulated Raman Scattering of SrWO4 Crystal

Stimulated Raman scattering (SRS) of picosecond pulses is investigated in a new crystal SrWO4. The second harmonic generation of a mode-locked Nd:YAG laser system is used as the pump source. In an external single-pass configuration, the SRS thresholds for the first to the fourth Stokes lines are measured. For the first Stokes line, the steady-state gain coefficient of the SrWO4 crystal is calculated to be 15.96 cm/GW. In our experiment, as many as five Stokes lines (559.23 nm, 589.61 nm, 623.49 nm, 661.50 nm, 704.44 nm) and three anti-Stokes lines (506.97 nm, 484.34 nm, 463.65 nm) are observed, and the total conversion efficiency is as high as 62%.

Laser Diode-Pumped Nd:LuVO4 Acousto-Optic Q-Switched Laser at 916 nm

A compact laser diode-pumped solid-state Nd:LuVO4 acousto-optic Q-switched laser is demonstrated at 916 nm of a quasi-three level for the first time. A pulse width of 130 ns is observed when the pulse-repetition frequency is 10 kHz. The laser experiment shows that the Nd:LuVO4 crystal can be used for efficient diode-pumped Q-switched lasers.

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%.

Passively Mode-Locked Quasi-Three-Level Nd:LuVO4 Laser with Semiconductor Saturable Absorber Mirror

We demonstrate a passively cw mode-locked Nd:LuVO4 laser operating on the quasi-three-level at 916 nm with a Z-folded resonator. Using a semiconductor saturable absorber mirror (SESAM) as the passive mode-locking device, we achieve stable cw mode locking with 6.7 ps pulse duration at repetition rate of 133MHz and 88mW average output power under the pump power of 17.1 W.

Passively Q-Switched Nd:KLuW Laser with Semiconductor Saturable Absorber

A simplified n- ZnO/ p- Si heterojunction has been prepared by growing n- type ZnO rods on p- type silicon wafer through the chemical vapour deposition method. The reflectance spectrum of the sample shows an independent absorption peak at 384 nm, which may be originated from the bound states at the junction. In the photoluminescence spectrum a new emission band is shown at 393 nm, besides the bandedge emission at 380 nm. The electroluminescence spectrum of the n- ZnO/ p- Si heterojunction shows a stable yellow luminescence band centred at 560 nm, which can be attributed to the emission from trapped states. Another kind of discrete ZnO rod has also been prepared on such silicon wafer and is encapsulated with carbonated polystyrene for electroluminescence detection. This composite structure shows a weak ultraviolet electroluminescence band at 395 nm and a yellow electroluminescence band. These data prove that surface modification which blocks the transverse movement of carriers between neighbouring nanorods plays important roles in the ultraviolet emission of ZnO nanorods. These findings are vital for future display device design.

Ce, Pr:YLuAG原料合成、晶体生长及LED应用

Ce,Pr:YLuAG pure phase powder was synthesized by co-precipitation method and calcined at 1450°C, which had a garnet structure. The feed rod was prepared by press forming and solid state sintering. TEM showed that the sintered rod had good crystallinity and density. Ce,Pr:YLuAG single crystal was grown by the floating zone method. The as-grown crystal was transparent with a pale yellow color, and small cracks were observed in the shoulder. The transmittance of the crystal is 81.8%, which is close to the theoretical value 84.2%. Under 460 nm excitation, Ce,Pr:YLuAG crystal shows the emission band of Ce at 530 nm and peak of Pr at 610 nm, which shows that Ce can transfer the energy to Pr. However, only Pr emission peak appears when it is excitated at 487 nm. The color coordinate is located at (0.474, 0.495) which shifts to red zone compared with commercial Ce:YAG yellow phosphor. As a result, Ce,Pr:YLuAG crystal is more suitable to fabricate white LED.

Scintillating properties of LiYSiO4:Ce

LiYSiO4:Ce is a promising scintillator and some of its properties have been reported in previous papers. In this paper, samples doped with different concentrations of Ce are prepared and studied. First, the relative light yields of the samples are measured as 28.1%-37.1% compared with a standard ant...