H. T. Huang

V 3+ :YAG as the saturable absorber for a diode-pumped quasi-three-level dual-wavelength Nd:GGG laser

The performance of a diode-end-pumped passively Q-switched dual-wavelength Nd:GGG laser operating at 932.9 and 936.5 nm with V(3+):YAG as the saturable absorber was demonstrated for the first time to the best of our knowledge. The maximum dual-wavelength average output power of 150 mW was achieved with a T = 2% output coupler under the absorbed pump power of 2.55 W, corresponding to the optical-to-optical conversion and slope efficiency of 5.9% and 8.0%, respectively. The minimum pulse width was 395 ns with the pulse repetition frequency of 140 kHz, which was attained with a T = 5% output coupler under the absorbed pump power of 2.55 W.

Diode-pumped passively Q-switched Nd:Gd 0.5 Y 0.5 VO 4 laser at 1.34μm with V 3+ :YAG as the saturable absorber

The performance of a diode-pumped passively Q-switched Nd:Gd(0.5)Y(0.5)VO(4) laser at 1.34 microm with V(3+):YAG as the saturable absorber was demonstrated for the first time to the best of our knowledge. The focal lengths of thermal lens in the diode-end-pumped Nd:Gd(0.5)Y(0.5)VO(4) laser for the 1.34 microm transition was experimentally investigated, with the corresponding proportion constant estimated to be approximately1.5x10(4) W/mm. For the passive Q-switching operation, the maximum average output power of 0.96 W was achieved under the pump power of 7.28 W, corresponding to optical-to-optical conversion and slope efficiency of 13.2% and 17.6%, respectively. The minimum pulse width attained was 47.8 ns with the pulse repetition frequency of 76 kHz, with the single pulse energy and peak power estimated to be 8.7 microJ and 182 W, respectively.

A compact passively Q-switched intra-cavity frequency doubled Nd:YAG/Cr4+:YAG composite crystal green laser

A compact diode-end-pumped passively Q-switched intra-cavity frequency doubled Nd:YAG/Cr4+:YAG composite crystal laser was demonstrated. The pulsed laser at 532 nm was produced and the dependence of the average out power, pulse width and pulse repetition rate on incident pump power were measured. Under the pump power of 14 W, the minimum pulse width of 3.5 ns with repetition rate of 27.5 kHz was obtained, corresponding single-pulse energy of 18 μJ and peak power of 5.3 kW.

Compact efficient diode-end-pumped intracavity frequency-tripled Nd:YAG 355 nm laser

A compact efficient diode-end-pumped acousto-optically Q-switched intracavity-frequency-tripled Nd:YVO4 355 μm ultraviolet laser was realized. Intracavity sub-resonators with anti-reflection and high-reflection coated mirrors were used to get higher efficiency of third harmonic generation. With two LBO crystals used in frequency doubling and tripling processes, greater than 1.46 W 355 nm average output power was obtained under the absorbed pump power of 13.9 W and the repetition rate of 10 kHz. The corresponding pump-to-ultraviolet conversion efficiency was determined to be as high as 10.5%. At 10 kHz, the minimize pulse width was obtained to be 12 ns with the peak power of 10.4 kW and single pulse energy of 146 μJ.

12-W red light generation by frequency-doubling Q-switched Nd:YAG laser

By using a 15 mm-long type I phase-matching LBO crystal, a maximum quasi-continuous wave red laser output power of 12 W has been obtained by intra-cavity second-harmonic generation (SHG) in a compact acousto-optically Q-switched diode-side-pumped Nd:YAG laser. The corresponding optical-optical conversion efficiency is 6.6%. The power instability at the maximum output power is observed to be less than 4.62% during half an hour. The beam quality factor M2 is measured to be 9.9 ± 1.0 by the knife-edge method. The spectrum of the red radiation is also measured and discussed.

Highly efficient intracavity frequency doubling 532-nm laser based on the gray tracking resistance KTP crystal

Based on the gray tracking resistance (GTR) KTP crystals, the performance of a high efficient and compact intracavity frequency doubling 532 nm laser was investigated. The gray tracking test indicated that the KTP used in our experiment had good resistance to the gray tracking. The absorption coefficient of this GTR-KTP at 1064 and 532 nm were measure to be 5 × 10−3%/cm and 0.2%/cm, respectively. The maximum average output power of 40.6 W at 532 nm was obtained at the repetition frequency of 10 kHz for the 10 mm long GTR-KTP, which corresponded to 22.6% pump-to-green conversion efficiency. The effective conversion efficiency from the Q-switched 1064 nm to the green power at 10 kHz repetition rate was as high as 86.4%.

High beam quality and compact diode end-pumped Nd:YVO4 slab laser with a hybrid resonator

A compact, high power and high beam quality diode-end-pumped CW Nd:YVO4 slab 1064 nm laser with a hybrid resonator is demonstrated. The maximum output power of 23.0 W is obtained under the pump power of 66.7 W, which gives the slope efficiency and optical conversion efficiency of 52.0 and 34.0%, respectively. The beam quality M2 factors are measured to be 1.5 in the unstable direction and 1.7 in the stable direction. The power stability of the LD end-pumped slab laser at an output power of 19 W is measured to be 0.7% for half an hour operation.

Diode-pumped passively Q-switched and mode-locked Nd:GGG laser at 1.3 μm with V3+:YAG saturable absorber

Using V3+:YAG crystal as the saturable absorber, a diode-pumped passively Q-switched and mode-locked Nd:GGG laser operating at 1.3 μm is realized for the first time. The mode-locking modulation depth of nearly 100% has been achieved. The maximum output power and the single Q-switched pulse energy are 410 mW and 8.3 μJ. The mode-locked pulse inside the Q-switched pulse has a repetition rate of 349 MHz, and its average pulse width is estimated to be about 750 ps.

2 ns-pulse, compact and reliable microchip lasers by Nd:YAG/Cr4+ YAG composite crystal

A compact diode-end-pumped passively Q-switched composite Nd:YAG/Cr4+:YAG laser was demonstrated in this paper. At the incident pump power of 11.8 W, the shortest pulse width of 2.05 ns was obtained, corresponding to average output power of 1.15 W and repetition rate of 17.1 kHz. The single-pulse energy and peak power were estimated to be 67.3 μJ and 32.8 kW, respectively.

High peak power eye-safe intracavity optical parametric oscillator pumped by a diode-pumped passively Q-switched ND:GGG laser

By exploiting the diode-end-pumped Nd:GGG/Cr4+:YAG laser as the pump source, a high peak power gray-trace resistance KTP intracavity optical parametric oscillator at eye-safe wavelength was first demonstrated (to our knowledge). Under the incident diode power of 10 W, the maximum average output power of 320 mW at 1567 nm was obtained with the T = 33% output coupler. The corresponding signal pulse width and repetition rate were respectively 1.4 ns and 5.8 kHz. Due to the greatly reduced pulse repetition rate and short pulse width, the signal peak power was estimated to be as high as 39.4 kW.