Bi Yong

Reducing Thermal Effect in End-Diode-Pumped Laser Crystal by Using a Novel Resonator

We report a new way, i.e. double-end-pumping, to extend the stability range of a laser resonator, in advantage of making the thermal loading be effectively divided between the ends of the laser crystal to reduce the thermal effect, thus to extend the stability range. Using this new way, we experimentally obtained a 2.7-W cw laser source at 671 nm by intracavity frequency doubling of 1342 nm of a Nd:YVO4 laser based on the nonlinear crystal LiB3O5. The maximum pump power is 28 W, which is higher than 13 W of the single-end-pumping.

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.

Highly Efficient Continuous-Wave Mid-Infrared Intracavity Singly Resonant Optical Parametric Oscillator Based on MgO:PPLN

We present a compact all-solid-state cw mid-infrared intracavity singly resonant optical parametric oscillator (OPO) that is based on a self-fabricated 1-mm-thick 40-mm-long doped MgO periodically poled lithium niobate (MgO:PPLN). At a diode pump power of 15.6 W, the compact intracavity Nd:YVO4/MgO:PPLN OPO produced 1.9 W output power at 3.19?m, corresponding to conversion efficiency of 12.2% from the laser diode pump to OPO idler output.

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%.

Period and temperature tuning of cascaded optical parametric oscillator based on periodically poled LiNbO3

We report the broadly tunable source by a cascaded optical parametric oscillator in the periodically poled LiNbO3 (PPLN) with domain grating period and temperature tuning. The optical parametric oscillator was pumped by a passive Q-switched Nd:YVO4 laser. Multi-wavelength outputs from visible to infrared were obtained. The temperature of the PPLN crystal changed within the range of 70-150°C with different periods of PPLN. The tunable range covered from 433 to 1657nm.

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.