Sun Zhi-Pei

High-power blue light generation by external frequency doubling of an optical parametric oscillator

We report on an all-solid-state high-power quasi-continuous blue light source by the frequency doubling of a signal wave from an optical parametric oscillator (OPO). A 50-mm-long LiB3O5 (LBO) crystal is used for the OPO, which is pumped by a diode-pumped Nd:YAG green laser (10 kHz, 50 ns). Tunable blue emission in a new nonlinear crystal BiB3O6 (BiBO) is obtained with a wavelength range from 450 to 495 nm. The average power of the signal output is as high as 9.3 W from 924 to 970 nm. The maximum output of the blue laser with the second harmonic walk-off compensation is 1.3 W average power at 470 nm for 6.2 W of OPO signal light at 940 nm.

High Beam Quality Green Generation with Output 140 W Based on a Thermally-Near-Unstable Flat–Flat Resonator

By using a diode-side-pumped Q-switched Nd:YAG rod laser based on a thermally-near-unstable flat-flat resonator, an intracavity-frequency-doubled green beam generation is investigated. Output power 140 W is obtained at a repetition rate of 10 kHz and a pulse width of 110 ns. The green beam quality factors M-x(2) and M-y(:)2 which are measured by a laser beam analyser, are 10.65 and 10.85, respectively. at output, power of 124 W.

Mid-infrared generation based on a periodically poled LiNbO3 optical parametric oscillator

We report a nanosecond Nd:YVO4-pumped optical parametric oscillator (OPO) based on periodically poled LiNbO3 (PPLN). Tuning is achieved in this experiment by varying the temperature and period of the PPLN. The design of double-pass singly resonant oscillator (DSRO) and confocal cavity enables the OPO threshold to be lowered considerably, resulting in a simple, compact, all-solid-state configuration with the mid-infrared idler powers of up to 466mW at 3.41μm.

Efficient Dual-LBO Second-Harmonic Generation by Using a Polarization Modulation Configuration

We analyse the relationship of conversion efficiency with the inter-crystal phase shift by the heuristic theory and propose a novel configuration of two cascaded nonlinear crystals for the second-harmonic generation with the polarization modulation. With this configuration, 70% external doubling efficiency is obtained, which is, to the best of our knowledge, the highest conversion efficiency with LBO crystal external frequency doubling. This configuration provides a simple and effective method to improve the second harmonic conversion efficiency.

Investigation on performance of high repetition diode-pumped heat-capacity Nd : YAG laser

We demonstrate the improvements of both beam quality and thermal depolarization loss of an all-solid-state heat-capacity Nd:YAG laser with repetition rate of 50 Hz, for the first time to our best knowledge, compared with the conventional steady-state laser. The beam quality of the heat-capacity laser has been improved three times higher than the conventional steady-state laser within the lasing periods of 60 s. The depolarization loss caused by thermo-optical effects which is definitely considerable in steady-state Nd:YAG laser has almost not been observed under heat-capacity operation. Design and operations of the all-solid-state heat-capacity Nd:YAG laser with average output power of 25 W with repetition 50 Hz are also studied with the optical-to-optical efficiency of 33.3%.

High-Power Red Light Generation by Intra-Cavity Frequency-Doubling of a Side-Pumped Nd:YAG Laser in a LiB3O5 Crystal

We report the generation of high-power red light radiation of 11.2 W in a LiB3O5(LBO) crystal with intra-cavity frequency doubling of two compact and simple side-pumped Nd:YAG laser modules under a repetition rate of 3.5 kHz. The pulse width of output is about 180±20 ns. The beam quality of the M2 value is 15±3 in both the directions. This excellent laser performance demonstrates that the Nd:YAG laser with LBO intracavity frequency doubling is an promising method for generating red light with high brightness.

Mid-Infrared Optical Parametric Oscillator Based on All-Solid-State-Pumped Periodically Poled LiNbO

We report the tunable mid-infrared generation with a periodically poled LiNbO3 (PPLN). Using an all-solid-state-pumped Nd:YVO4 laser as the pump source and a PPLN nonlinear crystal with grating periods of 28.2-30.8 mum, we have achieved wavelength conversion in the 2.90-4.05 mum spectral range by period tuning. The use of confocal cavity design has brought a compact, all-solid-state configuration with an average output powers of idler up to similar to 200 m W. The maximum power of 277 mW was obtained at the wavelength of 3.35 mum.