208-W TEM00 operation of a diode-pumped Nd:YAG rod laser

208-W average-power TEM(00) -mode operation from a diode-pumped Nd:YAG rod laser was demonstrated. The side-pumping method of generating a high-gain aberration-free rod, the bifocusing-compensation technique with two identically pumped rods, and a suitable choice of beam spot size were employed in the design of this laser. At the maximum pump power of 1.1 kW the fundamental transverse-mode operation (M(2)<1.1) was characterized by 7.6% electrical efficiency. The extraction efficiency was almost 60% of full multimode operation. Stable operation was obtained within a pump-power range of 15% of the maximum pump power.     

8-mJ TEM(00) diode-end-pumped frequency-quadrupled Nd:YAG laser

A frequency-quadrupled Nd:YAG laser pumped by a commercially available high-brightness stack is described. A master oscillator power amplifier configuration was implanted, and the laser delivered energy of 8 mJ at 0.266microm . The laser was air cooled for easy use.     

高功率高光束质量脉冲Nd: YAG激光器

 以实现高功率、高光束质量的脉冲激光输出为目的,对非对称平-凹谐振腔的结构进行了理论分析。设计出了高功率、高光束质量非对称放置的平-凹谐振腔、双氙灯泵浦的脉冲Nd: YAG激光器。当占空比为9%时,实现输出激光平均功率近480 W,光束参数积优于12.7 mm·mrad,电光转化效率近4%,与理论分析吻合,可用芯径300 μm的光纤传输,不稳定性优于±1%。加工实验证明有较好的质量：切割材料为不锈钢,厚度为3 mm时、切割速度为0.6 m/min和厚度为1.5 mm、切割速度为1.2 m/min时,两种情况下所得切缝宽度均为250 μm,且切割上下沿光滑。     

高功率高光束质量脉冲Nd: YAG激光器

以实现高功率、高光束质量的脉冲激光输出为目的,对非对称平-凹谐振腔的结构进行了理论分析。设计出了高功率、高光束质量非对称放置的平-凹谐振腔、双氙灯泵浦的脉冲Nd: YAG激光器。当占空比为9%时,实现输出激光平均功率近480 W,光束参数积优于12.7 mm·mrad,电光转化效率近4%,与理论分析吻合,可用芯径300 μm的光纤传输,不稳定性优于±1%。加工实验证明有较好的质量：切割材料为不锈钢,厚度为3 mm时、切割速度为0.6 m/min和厚度为1.5 mm、切割速度为1.2 m/min时,两种情况下所得切缝宽度均为250 μm,且切割上下沿光滑。     

High efficiency diode laser side-pumped Nd:YAG rod laser

High efficiency laser performance of 2 mm diameter and 20 mm long Nd:YAG crystal rod transversely pumped by laser diode array is presented. Using the directly side-coupled geometry enclosed by cylindrical pump cavity plated with gold, we obtained long pulse energy of 4.6 mJ corresponding to optical-to-optical slope efficiency of 37%. The complete solid-state Nd:YAG laser is described to be simple, compact and highly efficient. Q-switching of the laser is also reported.     

LD端面泵浦Nd:YAG/BIBO单模蓝光激光器

从理论上分析了准三能级系统946 nmNd:YAG全固态激光器运转的条件,并比较了几种不同的倍频晶体的特性,给出内腔倍频获得473 nm蓝光发射的方案。用波长808 nm、输出功率为2.2 W的半导体激光器泵浦Nd:YAG,采用内腔倍频的方法,在一定的温度下,用Ⅰ类临界相位匹配B IBO晶体倍频获得了473 nm 26.5 mW的单模连续蓝色激光输出,功率波动小于±5%。     

A birefringence-compensated two-rod Nd:YAG laser operating in TEM00 mode with a CW 61W output power

Two identically pumped Nd:YAG rods with a imaging system and a polarization rotator are used in experiments to achieve a complete birefringence compensation. The measured depolarization ratio is from 1.0 to 2.5%, which increases with the increasing of pump power. With a TEM₀₀-mode operation, the depolarization ratio achieved is less than 1%. A dynamically stable resonator is performed using two flat mirrors and an intra-cavity lens. 61 W linearly polarized output was achieved with a M ² factor of 1.6, which is the state of the art for a lamp pumped laser.     

Segmented circular LD arrays side-pumped a Nd:YAG laser rod

We design a Nd:YAG module with symmetrical LD side-pumped structure in a periodical arrangement between circular LD arrays and holders. This novel design has great potential to be used in compact and miniature laser systems. Design optimization and simulation on thermal effects have been performed. An experiment has also been carried out. The experiment results indicate the all-solid-state laser with the-Nd:YAG module can stably operate in the range of 10–30 Hz with no controlling temperature by TE cooler. The laser beam had a divergence angle less than 3.8 mrad and a maximum output pulse of 174 mJ has been obtained at the pump current of 50 A and working frequency of 23 Hz, corresponding to optical-optical conversion efficiency of 40.2%.     

High power CW diode-side-pumped Nd:YAG rod laser

We report on the characterization of a diode-side-pumped Nd:YAG rod laser operating at high CW output power. A four-fold pump configuration is designed and the pump light is directly coupled into the Nd:YAG rod without the help of any cylindrical lenses. The distribution of pump light in the Nd:YAG rod has been calculated by using ray tracing program. The thermal lens effect of the Nd:YAG rod has been experimentally measured. A maximum output power of 800 W at 1064 nm in multimode operation is obtained for a pump power of 2400 W with 33% optical-optical efficiency. At the same time, the maximum beam parameter product of 25 mm·mrad is achieved.     

28% electrical-efficiency operation of a diode-side-pumped Nd:YAG rod laser

We propose a highly efficient quasi-cw Nd:YAG rod laser with a novel side-pumping design that uses microlens-free diode stacks. We demonstrate 320-W output power with 28% electrical-to-optical efficiency, which is, to our knowledge, the highest efficiency reported for diode-pumped solid-state lasers.     

Quality of the beam produced a pulsed Nd:YAG laser

The quality of the beam produced by a Nd:YAG laser was investigated. A hemispherical Nd:YAG laser resonator was developed. A flashlamp driver was designed to pump a Nd:YAG laser crystal. The output of the laser was characterized via the variation of the capacitor voltage. A phosphor card was used to detect the invisible of the infrared beam. Exposed photographic paper was utilized to examine the energetic beam after interaction. The brightness and strength of the beams were analyzed using the Matrox Inspector and VideoTest 5 software packages. The intensity of the beam produced and the volume loss after interaction were found to linearly increase with respect to the input energy.     

468-W CW operation of a diode-pumped Nd:YAG rod laser with high beam quality and highly efficient concentrator of pump light

A novel design of an efficient, highly reliable, and good beam quality diode-pumped solid-state laser for precise material processing application is presented. Effort has been done to obtain a highly uniform pumping intensity in the active area, which simultaneously reduces the effects of thermal gradient. In this design a novel lens duct configuration which send the light into the center of the rod is used. By this way a uniform power distribution and a maximum absorption of pump power is resulted. Adopting this design, the maximum laser power of 468 W with optical to optical efficiency of 33% in CW mode and M² factor of less than 15 is obtained. Numerical analysis also indicates the superiority of the design to other methods such as direct and diffusive pumping techniques.     

Improvement in solar-pumped Nd:YAG laser beam brightness

Solar-pumped solid-state lasers are promising for renewable extreme-temperature material processing. Here we report a large improvement in solar laser beam brightness by pumping a thin Nd:YAG single crystal rod. A fused silica light guide of 14 mm×22 mm rectangular cross-section is used to both transmit and homogenize the concentrated solar radiation from the focal zone of a 2.88 m² parabolic mirror to the entrance aperture of a modified 2D-CPC flooded pump cavity, within which a 4 mm diameter rod is efficiently pumped. 2.2% slope efficiency is reached. Laser beam brightness figure of merit B is three times higher than that of the most recent solar-pumped Nd:YAG laser by a Fresnel lens. The introduction of the rectangular cross-section light guide has also ensured a much more stable laser emission than previous pumping schemes.     

High power and high beam quality CW green beam generated by diode-side-pumped intracavity frequency doubled Nd:YAG laser

We report a stable high power and high beam quality diode-side-pumped CW green laser from intracavity frequency doubled Nd:YAG laser with LBO crystal. By using a advanced resonator, a large fundamental mode size in the laser crystal and a tight focus in the nonlinear crystal could be obtained simultaneously, which are favorable for high power and high beam quality CW green laser generation. The green laser delivered a maximum 532 nm output power of 40 W. The corresponding optical-to-optical conversion efficiency and electrical-to-optical conversion efficiency were 8.6% and 5.0%, respectively. Under 532 nm output power of 34 W, the beam quality factor was measured to be 1.6.     

High power high beam quality diode-pumped 1319-nm Nd:YAG oscillator-amplifier laser system

This paper demonstrated a high power and high beam quality diode-pumped 1319-nm Nd:YAG master oscillator-power amplifier laser system. A thermally near-unstable resonator with four-rod birefringence compensation flat--flat cavity was adopted as the master oscillator. A solid etalon was inserted in the unidirectional ring resonator to compress the laser linewidth. Under a repetition rate of 500~Hz and pulse width of 160~\mus, the master oscillator delivers an average output power of 16.8~W at 1319~nm with linear polarisation, beam quality factor M^{2} = 1.16 and linewidth of 3.2~GHz. A double-pass power amplifier with two amplifier stages was employed for higher power scaling and the output power was amplified to be 25.9~W with M^{2} = 1.43.     

LD side-pumped 41 W high beam quality acousto-optical Q-switched single-rod Nd:YAG laser

We report a LD side-pumped high beam quality (M _x ² = 1.20 and M _y ² = 1.19) acousto-optic (AO) Q-switched single-rod Nd:YAG laser with a TEM₀₀-mode dynamic stable cavity. At the pump power of 600 W, 41 W TEM₀₀-mode 1064 nm laser was achieved with electro-optical conversion efficiency of 7%. The repetition rate and pulse width were 30 kHz and 102 ns, respectively with pulse energy of 1.4 mJ and peak power of 13 kW. Up to 24 W of 532 nm green laser was generated by external frequency doubling, corresponding to 59% optical conversion efficiency.     

Cutting of nonmetallic materials using Nd:YAG laser beam

This study deals with Nd:YAG laser cutting nonmetallic materials, which is one of the most important and popular industrial applications of laser. The main theme is to evaluate the effects of Nd:YAG laser beam power besides work piece scanning speed. For approximate cutting depth, a theoretical study is conducted in terms of material property and cutting speed. Results show a nonlinear relation between the cutting depth and input energy. There is no significant effect of speed on cutting depth with the speed being larger than 30 mm/s. An extra energy is utilized in the deep cutting. It is inferred that as the laser power increases, cutting depth increases. The experimental outcomes are in good agreement with theoretical results. This analysis will provide a guideline for laser-based industry to select a suitable laser for cutting, scribing, trimming, engraving, and marking nonmetallic materials.     

Compact TEM00 Nd:YVO4 slab laser end pumped by an LD bar

In this paper, we present a laser-diode (LD) bar end-pumped Nd:YVO₄ slab laser, which uses a simple coupling system and a compact quasi-concentric resonator (QCR). A TEM₀₀ output was obtained with a pump width varied from 2.57 to 9.44 mm and the slope efficiency is kept at about 48%. Under 40-W pumping, a maximum TEM₀₀ output of 15.84 W was achieved and the optical-to-optical efficiency was 39.6% correspondingly.     

Fiber Raman laser pumped by a Nd:YAG laser

We have pumped a fiber Raman laser with a cw mode-locked Nd:YAG laser operating at 1319 nm and generated pulses as short as 160 fsec using soliton pulse shaping in the fiber. We have also constructed a completely integrated oscillator loop using a fiber optic coupler and fusion splicing.