Efficient multiple-longitudinally diode laser pumped Nd:YAG slab laser

The operation of an eightfold longitudinally diode laser pumped 1.06m cw Nd:YAG slab laser is demonstrated. The 809 nm diode radiation is focused through a dichroic coating into each laser channel starting from the reflection points of the 1.06m beam in the slab crystal. At an absorbed pump power in the crystal of 2830 mW a maximum cw TEM₀₀ output of 1075 mW was achieved with a corresponding slope efficiency of 42.5%.     

High performance Cr4+:YAG Q-switched CW diode pumped Nd:YAG laser

This paper reports the operation of a Cr4+:YAG Q-switched CW diode laser pumped Nd:YAG at 1064nm. The laser performances resulted in 167 μ J, 21ns pulses at 10kHz, and 1.67W power output. When intracavity polarized, stable amplitude (fluctuations <±1%), TEM00, 153 μ J pulses were generated allowing 50% SHG in KTP. This revised version was published online in November 2006 with corrections to the Cover Date.     

Passively Q-switched,high peak power Nd:YAG laser pumped by QCW diode laser

A Nd:YAG laser passively Q-switched by a Cr:YAG showed a high single pulse energy of 53.0 mJ and 5.1 MW peak power. The laser was pumped by quasi-continuous-wave diode bars from single side. The Q-switched pulse had optical-to-optical efficiency of 12% and average temporal duration of 10.4 ns when Cr:YAG with initial transmission of 9.0% was used. Intense pumping as well as very low initial transmission of the saturable absorber gave very high peak power.     

Optical parametric oscillator pumped by relaxation oscillation pulses of a mechanically Q-switched Nd:YAG laser

We report the generation of mid-infrared pulsed radiation between 2.2 and 3 μm range using a singly-resonant optical parametric oscillator (SR-OPO) based on a 40-mm-long crystal of periodically-poled LiNbO₃ (PPLN) pumped by mechanically Q-switched pulses from a Nd:YAG laser, obtained by chopping the beam inside the laser resonator over a 1–10 kHz duty cycle. An appreciable reduction in pulse width as well as the number of relaxation oscillation pulses of the Nd:YAG pump laser is observed when the frequency of the Q-switch chopper is increased up to 10 kHz. Sub-nanosecond relaxation oscillation pulses of about 170–210 ns duration are generated under the width of the idler envelope varying from 4.6 to 8.55 μs. The same behavior is observed for the signal wave. A maximum extraction efficiency of 22 % is obtained for the idler, corresponding to 785 mW of output power at 10 kHz. The tuning of the signal and idler beams were performed by temperature variation of the PPLN crystal within 100–200 °C range.     

A passively Q-switched diode pumped Yb:YAG microchip laser

A passively Q-switched diode pumped Yb:YAG microchip laser with Cr4+:YAG saturable absorber mirror is reported. The TEMoo laser pulses are obtained with 1,7-uJ pulse energy, 15-ns pulse width, 0.11-kW peak power, and a repetition rate of 2.2 kHz at 1049 nm. The doped concentration and dimension of Yb:YAG microchip crystal are 10 at.-% and 5×0.6 mm2, respectively.     

100W二极管泵浦Nd:YAG薄片激光器

报道了一台高效率二极管泵浦Nd:YAG薄片激光器,采用高效均匀泵浦耦合技术,在峰值功率1.008kW,占空比25％, 电-光效率大于45%的二极管激光阵列泵浦下,用一块1mm厚的Nd:YAG薄片激光介质,获得了峰值功率404W,平均功率101W的准连续激光输出,光-光效率达到40%,电-光效率超过18%。     

LD泵浦的Nd：YAG调Q激光器腔内倍频研究

DPL的调Q倍频是获得高重复率绿光输出的有效方法,本文研究了这种激光器的动态特性,提出存在使转换效率最高的最佳非线性耦合系数,它是调Q时反转粒子数超阈值倍数的函数.实验用国产200mWR的MQW—LDA泵浦Nd:YAG激光器,声光调Q,KTP腔内倍频,输出0.4μJ的倍频光,脉宽70ns,峰功率6W.     

Efficient femtosecond Yb:YAG laser pumped by a single-mode laser diode

Single-mode diodes enable a particularly simple, compact and effective pumping of solid-state laser devices for many specialized applications. We investigated a single-mode, 300-mW laser diode for pumping at 935 nm a Yb:YAG laser passively mode-locked by a semiconductor saturable absorber. Relatively short pulse generation (156 fs), tunable across 1033–1059 nm has been demonstrated. An optical-to-optical efficiency of about 28% has been obtained with 320 fs long pulses. Therefore, contrarily to what previously believed, compact diode-pumped ultrafast Yb:YAG oscillators can reliably and efficiently deliver pulses in the range of ≈ 100–200 fs with few tens of mW, which are very appealing for bio-diagnostics and amplifier seeding applications.     

二极管泵浦Nd:YAG圆片激光技术研究

介绍了热容激光技术的发展历史及现状,介绍了固体激光器热容方式工作的基本原理,报道了二极管泵浦NdYAG圆片激光器热容方式工作的实验结果.用热像仪测量了激光器工作时增益介质通光面上的温度分布特性;采用干涉测量的方法测量了工作中的增益介质的与光束传输方向相垂直的方向上的折射率分布特性;结果表明片状固体增益介质热容方式工作对振荡光束波前畸变影响很小.给出了与光束传输方向相垂直的截面上增益介质的荧光分布.得到输出平均功率达47.5 W,此时的光-光转换效率为17%.     

Diode pumped Nd:YAG laser repetitively Q-switched with Cr4+:YAG

Based on the rate equations of passively Q-switched solid state lasers, the performance of laser at a fixed pump power can be optimized through the proper choice of output coupler and the low-intensity transmission of saturable absorber. A simple expression for optimizing these two parameters is derived in this paper. We also demonstrate the performance of an efficient diode-pumpe Cr⁴⁺:YAG passively Q-switched Nd:YAG laser to generate a high-repetition-ate, high-peak power 1064 nm laser pulses, which providing pulses peak power > 10 kW with high repetition rate up to 150 kHz, and the pulse width as short as 6.8 ns.     

Pulse-series 1.57 μm optical parametric oscillator pumped by a Q-switched Nd:YAG laser with a variable reflectivity mirror

A method of generating 1.57 μm pulse-series eye-safe laser based on optical parametric oscillator (OPO) was developed. The 1.57 μm pulse-series OPO was pumped by a Q-switched Nd:YAG laser with a variable reflectivity unstable resonator. Every pulse-series includes three micro-pulses, and the pulse repetition rates, pulse numbers and pulse intervals were adjustable. The maximum output energy of the 3-micro-pulse-series was 274 mJ. The optical-optical efficiency of the OPO was about 40%.     

交叉棱镜腔Nd:YAG板条激光器

对稳定和非稳共焦型Nd:YAG板条激光器的特性作了理论分析和实验研究.证实了使用交叉棱镜腔的流动空气-水混合冷却板条激光器有高的光束质量和对棱镜失调的不灵敏性,可望获得某些实际应用.关键词:交叉棱镜腔,板条激光器.     

A diode end-pumped passively Q-switched Nd:YAG/KTA Raman laser

A diode end-pumped passively Q-switched Nd:YAG/KTA intracavity Raman laser is presented. A KTA crystal with a size of 5 mm × 5 mm × 25 mm is used as the Raman active medium and its 234 cm^?1 Raman mode is employed to finish the conversion from 1064 nm fundamental laser to 1091 nm Raman laser. A 2 mm thick Cr⁴⁺:YAG crystal is used as the saturable absorber. With an LD pump power of 7.5 W, the first-Stokes power of 250 mW is obtained with a pulse repetition frequency of 14.5 kHz. The corresponding diode-to-Stokes conversion efficiency is 3.3% and the pulse energy is 17.2 μJ. Pulse width is measured to be 12.6 ns and peak power is 1.4 kW.     

Greatly improved stability of passively Q-switched Ce:Nd:YAG laser by using corner cube prism

In order to solve the hard problem of laser instability, a miniature Cr⁴⁺:YAG Q-switched Ce:Nd:YAG laser with a retroreflecting corner cube prism is demonstrated. The corner cube prism is insensitive to misalignment in any direction. Laser cavity with the prism is found to meet the condition of violent change of environment temperature and the variation of thermal lens of laser crystal by our experiment. Compared with flat-flat cavity, stability of the laser with a retroreflecting corner cube prism is improved remarkably.     

Nd:LuYAG混晶1123 nm被动调Q激光器

文章报道了一个二极管激光抽运的1123 nm被动调Q激光器. 激光晶体为混晶Nd:LuYAG, 饱和吸收体选为Cr⁴⁺:YAG晶体. 在连续运转情况下, 最高输出功率为2.77 W, 对应的光-光转换效率为29.53%. 调Q运转时, 在9.38 W吸收抽运功率下, 最高输出功率为0.94 W. 脉冲宽度整体在105 ns左右. 在最高吸收抽运功率下, 1123 nm激光的输出重复频率为9.40 kHz, 对应的单脉冲能量可达100 μJ, 高于目前报道的单晶Nd:YAG 1123 nm单脉冲能量, 证明其在能量存储方面较单晶Nd:YAG更具优势. 另外, 据我们所知, 这是关于混晶Nd:LuYAG 1123 nm输出的首次报道.     

Experimental analysis of a continuously pumped,repetitively Q-switched Nd/YAG laser

The threshold operation and performance of a high pulse repetition frequency Nd/YAG laser are discussed. A rotating mirror Q-switch was used, and detailed studies of the variation of Q-switched threshold with motor frequency, and of the pulse build-up time with input power have been carried out. The results indicate that the switching angle varies with mirror reflectivity but is practically independent of resonator length. The latter is attributed to thermal lens action in the laser rod modifying the nominally plane parallel resonator configuration thereby leading to a spherical configuration. Under these conditions, the switching angle becomes independent of resonator length, but depends strongly on the induced focal length of the lens (laser rod). The degrading effect on the Q-switched laser performance of the mis-match at the laser rod surfaces is then discussed and finally the conditions for achieving maximum energy output in a single pulse are derived and experimentally verified.     

Intracavity optical parametric oscillator pumped by an actively Q-switched Nd:YAG laser

A non-critically phase-matched KTiOPO₄ optical parametric oscillator (OPO) intracavity pumped by a laser diode end-pumped acousto-optically Q-switchedNd:YAG laser is experimentally demonstrated. The highest average power is obtained at the pulse repetition rate (PRR) of around 15 kHz, which is different from the widely reported Nd:YVO₄ laser pumped OPO in which the highest average power is obtained at a very high PRR, e.g. 80 kHz. With an incident laser diode power of 6.93 W and a pulse repetition rate of 15 kHz, an average signal power of 0.72 W is obtained with a peak power of 7.7 kW and an optical-to-optical conversion efficiency of 10.4%. PACS 42.65.Yj; 42.60.Gd; 42.55.Xi     

Solar pumped Nd:YAG laser

We report the high efficiency of solar pumped laser. The sunlight is concentrated by the concentrator system, which is composed by the Fresnel lens and the cone-channel condenser. The power density of sunlight concentrated by the concentrator system surpasses the lasing threshold for pumping laser. In the experiment, the sunlight concentrated is coupled into the conical chamber pumping Nd:YAG laser media. Laser output of 3.5 W has been achieved; the collect efficiency is 3.5 W/m². The conversion efficiency is 1.0% from solar power into laser, and the slope efficiency is achieved 1.86%.     

High peak power Nd:YAG laser pumped by 600-W diode laser stack

The Q-switched laser with triangle slab made of Nd:YAG crystal side pumped by 600-W quasi-cw diode laser stack has been designed. The multimode (M²≈2.6) output energy of about 42 mJ was demonstrated in free running mode for110-mJ pump energy. In Q-switch experiments, the KDDP Pockels cell was placed between the slab and rear mirror in plane-plane cavity with output coupler of 84% transmission. The energy of 8 mJ in 2.1-ns pulse duration was obtained for near TEM₀₀ output beam. For passive Q-switching by means of Cr:YAG crystal of 12.6% unsaturated transmission, the energy of 5.1 mJ in 2.5-ns pulse duration was obtained for output beam close to TEM₀₀ mode.     

Thin Nd:YAG slab laser pumped by lens duct coupled diode laser stacks

High power continuous wave operation of a diode face-pumped thin Nd:YAG slab laser is reported. A novel pumping geometry for a thin Nd:YAG slab using cylindrical lens duct coupled diode laser stacks is demonstrated. In a close-coupled resonator, a maximum laser output power of 260 W in multimode operation is obtained. This corresponds to a slope efficiency of 34% and an optical-to-optical efficiency of 27%, respectively. In high-brightness operation, a polarized laser output of 70 W has been obtained with a beam quality factor close to 4 in both directions. The polarization contrast ratio is >100. PACS 42.55.Xi; 42.60.Pk; 42.60.By