500 W Nd:YAG zigzag slab MOPA laser

A MOPA Nd:YAG laser with end-pumped zigzag slab architecture has been developed. 277 W laser output is obtained from the master-oscillator stage, corresponding to the average slope efficiency of 35.9% and the optical conversion efficiency of 34.6%, which emits the maximum power of 402 with 1163 W of pump power. Furthermore, the amplifier stage produces 505 W with the slope efficiency of 24% and the extraction efficiency of 25%. The beam quality is estimated as M _x ² ≈ 10, M _y ² ≈ 50 in the orthogonal directions respectively.     

Performance of CW NYAB laser at 1.06 μm end-pumped by a high-power diode-laser-array

A CW NYAB laser at 1.06 μm end-pumped by a high-power diode-laser-array has been demonstrated. At the incident pump power of 11 W, a maximum output power of 3.2 W was achieved, resulting in an optical conversion efficiency of 29.1%, and average slope efficiency of 37.5%. The output beam quality factor was measured to be M²=1.9. The internal losses caused by the NYAB crystal were measured to be 0.035 cm⁻¹. The NYAB crystal was also found to exhibit very strong thermal lensing under high-power end-pumped conditions.     

激光二极管双端直接抽运混合腔板条激光器

为减少热透镜效应的影响, 获得高光束质量的激光, 本文利用激光二极管阵列双端直接抽运Nd:YVO₄, 采用负支共焦折叠混合腔结构, 获得最高功率为416 W 1064 nm的激光输出, 光–光转换效率为54.3%, 斜效率为61.6%. 在输出功率为370 W时, 光束质量因子M²在非稳腔和稳腔方向上分别为3.9和4.7.     

High-efficiency longitudinally-pumped miniature Nd:YVO4 laser

We report on fundamental and intracavity frequency-doubled emission in a miniature Nd:YVO₄ (3×3×1 mm) laser. A maximum slope efficiency of η_s=58.6%, with optical efficiency of η₀=53.0% at 780 mW pump power was realized in a TEM₀₀ output beam. To obtain the optimum pump-beam focusing conditions we applied a new formalism in which the pump-beam propagation in the active medium was described by its M² factor. A good agreement between theoretical predictions and experimental results was observed. In second-harmonic regime, obtained by a KTP crystal, 230 mW green power that corresponds to 54% nonlinear conversion efficiency was reached.     

High power diode single-end-pumped Nd:YVO4 laser

A fiber-coupled diode-single-end-pumped Nd:YVO₄ laser with an Nd:YVO₄ crystal of 0.3 at% doping concentration and 3×3×10 mm³ dimensions was reported. 14.850 W of continuous-wave output power in an M² factor of 1.12 was obtained under pump power of 27.365 W, with an optical conversion efficiency of 60.49%, and a slope efficiency of 64.5%.     

Compact, efficient diode-end-pumped Nd:GdVO4 slab continuous-wave 912-nm laser

A fiber-coupled laser-diode (LD) end-pumped Nd:GdVO₄ slab continuous-wave (CW) 912-nm laser and an LD bar end-pumped Nd:GdVO₄ slab CW 912-nm laser are both demonstrated in this paper. Using the fiber-coupled LD of end-pumped type, a highest CW 912-nm laser output power of 10.17 W is obtained with a high optical-to-optical conversion efficiency of 24.6% and a slope efficiency of 34.5%. The measured M² factors of beam quality in x and y directions are 5.3 and 5.1, respectively. Besides, an LD bar of end-pumped type is used to realize CW 912-nm laser output, which has the advantages of compactness and low cost. When the pump power is 38.8 W, the output power is 8.87 W and the measured M² factors of beam quality in x and y directions are 16 and 1.31, respectively. In order to improve the beam quality of the 912-nm laser at x direction, a new quasi-concentric laser resonator will be designed, and an LD bar end-pumped Nd:GdVO₄ slab high-power CW 912-nm TEM₀₀ laser will be realized in the future.     

Efficient diode-pumped Nd:YVO4 continuous-wave laser at 1.34 μm

We report a high-power continuous-wave(cw) diode-pumped efficient 1.34 μm Nd:YVO₄ laser. The laser properties of a low Nd³⁺-doped concentration of the Nd:YVO₄ crystal operating at 1.34 μm formed with a simple plane-concave cavity have been demonstrated. With the incident pump power of 22 W, an output power of 8.24 W was obtained, giving an optical conversion efficiency of 37.5% and slope efficiency of 40%. The thermal effects of cw end-pumped solid-state lasers were studied.     

High-power 888-nm-pumped Nd:YVO4 1342-nm oscillator operating in the TEM00 mode

We report on a high-power 888-nm-pumped continuous-wave Nd:YVO₄ laser at 1342 nm. An output power of 24 W emitted into a diffraction limited beam with an M ² parameter better than <1.1 is demonstrated. At an absorbed pump power of 84 W the optical conversion efficiency is 29%.     

High beam quality and compact diode end-pumped Nd:YVO<Subscript>4</Subscript> 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-laser-array end-pumped 14.3-W CW Nd:GdVO4 solid-state laser at 1.06 μm

A diode-laser-array end-pumped efficient CW Nd:GdVO₄ laser at 1.06 μm has been developed. A low-order-mode output power of 14.3 W was obtained at the maximum available pump power of 26 W, giving an optical conversion efficiency of 55% and an average slope efficiency of 62%. The laser output beam quality factor at full pump power was determined to be M²<1.8. It is also shown that only lightly doped Nd:GdVO₄ crystals are suitable for high-power end-pumped lasers. Received: 4 May 1999 / Published online: 29 July 1999     

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.     

A high efficiency Ho:YAlO<Subscript>3</Subscript> laser pumped by Tm:YLF laser with a Volume Bragg Grating

We report a CW Ho:YAlO₃ (Ho:YAP) laser at room temperature pumped by a Tm:YLF laser with a Volume Bragg Grating (VBG) instead of the conventional mirror. The Ho:YAP laser operated at 2117.9 nm with output power 9.12 W. The optical-to-optical conversion efficiency is 60.4% and slope efficiency is 71.2%. The Ho:YAP output wavelength is centered at 2117.9 nm with bandwidth of about 1 nm. The beam quality factor is M ² ∼ 1.29 measured by the traveling knife-edge method.     

High-power diode-pumped Tm:YLF slab laser

A 2% Tm³⁺-doped LiYF₄(Tm:YLF) slab is double-end-pumped by two laser diode stacks. The pumped volume has a rectangular cross section. The Tm:YLF laser produced 148 W of continuos-wave output at 1912 nm in a beam with M _x ²≈199 and M _y ²≈1.7 for 554 W of incident pump power. The slope efficiency with respect to the incident pump power was 32.6%, and the optical-to-optical efficiency was 26.7%.     

High-power continuous-wave Nd:GdVO4 slab laser pumped directly into the F3/2 emitting level

95.6 W continuous-wave laser power output in 880 nm LD partially end-pumped Nd:GdVO₄ slab laser with a hybrid resonator is presented. The slope efficiency and optical-to-optical efficiency were 46.5% and nearly 42.6%, respectively. At the output power of 82 W, beam quality M² factors were 1.1 in the unstable direction and 1.36 in the stable direction, respectively.     

High-power and efficiency continuous-wave operation of <Emphasis Type="Italic">a</Emphasis>-cut Ho:YAP laser at room temperature

We report the continuous-wave (CW) operation of a room-temperature a-cut Ho:YAP laser resonantly end-pumped by a diode-pumped Tm:YLF laser at 1.91 μm. A maximum CW output power of 14.6 W at 2118.7 nm for a-oriented Ho:YAP was obtained, corresponding to the slope efficiency of 69.35% and optical-to-optical conversion efficiency of 63.04% with respect to absorbed pump power. The laser operated at a single mode (TEM₀₀) with the beam quality factor of M ² ∼ 1.51.     

High-power diode-end-pumped CW Nd:GdVO4 laser

We report on a high-power diode-end-pumped CW Nd:GdVO₄ laser. Under the pump power of 39.5 W, a maximum output power of 19.8 W and a slope efficiency of 58.5% were obtained. The beam quality M² at maximum output power was measured to be around 2.62. The thermal focal length in Nd:GdVO₄ crystal under the pump power from 22 to 40.6 W was measured. The pump-induced damage threshold was estimated to be 28.6 kW/cm².     

High-power, high-efficiency cw diode-pumped Tm:YAP laser emitting at 1.99?μm

We elaborate a high-power, high-efficiency cw Tm:YAP laser dual-end-pumped by the laser diode. With 41.9?W pumping power, we obtain a maximum cw output power of 14.7?W at 1988?nm with a slope efficiency of 43.8%, corresponding to an optical conversion efficiency of 35.1%. At the maximum laser output, we measure a beam quality of M ²?~?1.9.     

High power Q-switched TEM<Subscript>00</Subscript> Nd:YVO<Subscript>4</Subscript> laser with self-adaptive compensation of thermal lensing effect

a high power dual-end-pumped Nd:YVO₄ laser with adaptive compensation of thermal lensing effect by adjusting HR mirror along the optical axis was proposed. In Q-switching operation at 70 kHz, the laser worked at different pump power (from 90 W to 70 W) with stable beam quality (M ² ∼ 1.15) and high output power (from 39 to 28.4 W), corresponding to the absorbed-output conversion efficiency of 55%. In the meantime, the pulse duration was increased from 24 to 31.7 ns. At various repetition rate from 60 to 100 kHz, the beam quality factors were all measured less than 1.2.     

High efficiency continuous-wave single-frequency Nd:YVO<Subscript>4</Subscript> ring laser under diode pumping at 880 nm

An efficient single-frequency continuous-wave Nd:YVO₄ ring laser pumped at 880 nm is presented. With compact four-mirror ring cavity and optical isolator, we obtained an output power of 14.56 W at 1064 nm, corresponding to a slope efficiency of 61.7% and an optical-to-optical efficiency of 58.4% with respect to the absorbed pump power. The stability of the output power was better than ±0.5% over two hours. At the same time, a beam quality factor of M ²≈1.2 was measured and the line width of the longitudinal mode was about 25 MHz. To the best of our knowledge, this is the highest slope efficiency and optical-to-optical efficiency in single-frequency Nd:YVO₄ ring laser.     

Optimal design for a diode-pumped high-power high-efficiency high-beam-quality laser

We have demonstrated and analyzed a high-power high-efficiency high-beam-quality continuous-wave (cw) Yb:YAG laser, which is directly pumped into the upper lasing level by a fiber-coupled laser diode with a center wavelength of 969 nm. To achieve high efficiency and high beam quality simultaneously, we carried out a series of comparing experiments by changing the laser-medium length and pump-beam waist radius. From the cw Yb:YAG laser with a 5.0-at.%-Yb³⁺-doped and 5-mm-long crystal, an output power of 19.0 W has been obtained for a pump-beam waist radius of 138 μm. The maximum slope efficiency and optical-to-optical conversion efficiency are 78.9% and 55.3%, respectively. The M² factors of the laser beam are 1.33 in the vertical direction and 1.82 in the horizontal direction.