激光二极管泵浦的重复频率大能量低温Yb:YAG激光器设计

为实现重复频率大能量激光输出,基于Yb:YAG激光介质低温下良好的热特性和激光特性,设计了12 kW高功率激光二极管(LD)阵列泵浦的V型腔低温Yb:YAG激光器（液氮温度）。对于泵浦耦合系统和散热结构两个关键点,分别使用光线追迹方法和有限元方法进行了分析,提出了楔形真空窗口和低温热管等解决方案。模拟结果表明,该设计的激光器热效应较低,可实现重复频率大能量输出。     

激光二极管泵浦的重复频率大能量低温Yb:YAG激光器设计

为实现重复频率大能量激光输出,基于Yb:YAG激光介质低温下良好的热特性和激光特性,设计了12kW高功率激光二极管(LD)阵列泵浦的V型腔低温Yb:YAG激光器(液氮温度)。对于泵浦耦合系统和散热结构两个关键点,分别使用光线追迹方法和有限元方法进行了分析,提出了楔形真空窗口和低温热管等解决方案。模拟结果表明,该设计的激光器热效应较低,可实现重复频率大能量输出。     

Conductively-cooled,high-energy,single-frequency diode pumped slab laser for space applications

A laser-diode-pumped high efficiency, high pulse energy and single-frequency oscillator and amplifier for potential space environment applications have been developed and demonstrated using conductively-cooled heat removal. A diode-pumped injection seeded single-frequency oscillator was achieved by using the resonance-detection technique in Q-Switching operation, and Nd: YAG zigzag slabs based on “pump on bounce” are used in power amplifier stage for high-efficiency pulse energy extraction. Output pulse energy of 800 mJ with 11 ns pulse duration is obtained at a repetition rate of 100 Hz, with a near 3× diffraction-limit beam and an optical-to-optical efficiency of 18%. The experimental result shows that the laser has compact structure, high efficiency, reliability, conductive cooling and can be used for space environments.     

脉冲激光二极管泵浦调Q激光器泵浦时间特性研究

从调Q激光器的速率方程出发,对脉冲激光二极管泵浦的调Q激光器在不同泵浦功率及不同透过率情况下的最佳泵浦时间进行了理论分析。计算结果表明,在透过率为20%,腔内损耗为0.05的条件下,1—3倍阈值泵浦功率时,最高效率对应的最佳泵浦时间为1—1.5倍Nd∶YAG荧光寿命;7倍阈值泵浦功率及以上时,最佳泵浦时间约为荧光寿命的一半或者更短。在脉冲泵浦能量相同时,采用较短的泵浦时间(即泵浦功率较高),调Q输出的能量转换效率较高。     

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%.     

1645 nm Q-Switched resonantly pumped Er:YAG laser

A resonantly pumped Q-switched Er:YAG laser at 1645 nm was reported. 1 mJ of output pulse energy was achieved for Q-switched operation at 100 Hz repetition rate under total incident pump power of 4 W. An output peak power of 14 kW and pulse width of 60.6 ns were obtained.     

二极管泵浦高能激光研究进展和展望

高能激光广泛应用于材料加工、科学研究、空间碎片清除、军事应用等领域。二极管泵浦高能激光具有结构紧凑,系统简单、全电驱无限弹仓的特点,近年来,各类二极管泵浦高能激光围绕着同时实现高功率、高效率、高光束质量这一总目标发展迅速。详细综述了国内外高平均功率块状固体激光、高功率可见光波段激光、高峰值功率激光、高功率光纤激光、碱金属蒸气激光等二极管泵浦高能激光的研究进展,并对其发展趋势进行了展望。     

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%。     

1 kHz single-frequency,injection-seeded Er:YAG laser with an optical feedback

A novel 1 kHz single-frequency, Q-switched Er-doped yttrium aluminum garnet(Er:YAG) laser pumped by a 1470 nm laser diode is demonstrated. The 500 ns, 5.52 mJ single-frequency, diffraction-limited pulses are obtained by using a ‘ramp-fire' injection-seeding technique and an optical feedback architecture. The full width at half-maximum of the pulse spectrum is measured to be 1.47 MHz by using the heterodyne technique. The beam quality M2 factors are measured to be 1.18 and 1.24 in the x and y directions, respectively.     

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%.     

885 nm pumped,high efficiency single-frequency Nd:YAG ring laser

We report an efficient single-frequency ring laser pumped directly into emitting level by a fiber-coupled laser diode (FCLD) at 885 nm for the first time. 4.8 W laser at 1064 nm was obtained in a 0.7 at % Nd:YAG with 63% slope efficiency and 51.7% light-light efficiency in absorbed pump power. At the same time, the line width of the longitudinal mode was about 50 MHz, and the beam was nearly diffraction-limited with M2 ≈ 1.07.     

Resonantly pumped,high peak power Er:YAG laser

The high peak power hybrid Er:YAG laser, resonantly pumped at the wavelength of 1532 nm was developed. The fused silica acousto-optic modulator driven by 10 W of RF power was deployed as the Q-switch for such a laser. For the best case of Q-switching regime the pulses of 110 kW peak power (4 mJ, 37 ns) were reached at the pump power of 7.8 W and the repetition rate of 500 Hz.     

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.     

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.     

Resonantly pumped single frequency Er:YAG laser at 1645 nm

An efficient and single frequency Er:YAG laser pumped by an MGo:PPLN laser locked at 1532 nm with double F-P etalons was reported. The Er:YAG laser operated at 1645 nm, 550 mW of 1645 nm output was achieved under total incident pump power of 7 W. Using the etalons, 45 mW single frequency 1645.1 nm laser was achieved.     

Q-switched Er:YAG lasers resonantly pumped by Erbium fiber laser

The study describes efficient, acousto-optic Q-switching of Er:YAG laser at the 1645 nm eye-safe wavelength. For longitudinal pumping at wavelength 1532 nm, linear-polarized 10 W Erbium fiber laser radiation was used. The investigated Er:YAG crystals were 25 and 40 mm long and their Erbium concentration was 0.20 and 0.25%, respectively. For giant pulse generation, a fused silica acousto-optic modulator was inserted inside the Er:YAG laser oscillator. For a maximum incident pump power of 7.95 W, pulse energy up to 4.1 mJ was generated with pulse duration 34 ns at 500-Hz repetition rate; the corresponding peak power was 119 kW.     

1.6 μm Er:YAP and Er:YAG lasers resonantly pumped by Er:glass laser

1623 nm Er:YAP and 1648 nm Er:YAG lasers resonantly pumped by a solid state Er:glass laser operating at 1535 nm were investigated. Laser generation was reached for Er:YAP and two Er:YAG crystals with different Er ion concentration. The maximal output energies were 20 and 45 mJ for Er:YAP and Er:YAG laser systems, respectively.     

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.     

Laser diode array pumped Yb:YAG/BIBO 515 nm thin disc laser with four-pass optical coupling system

We presented a new simple flat-concave cavity system to produce compact and low-cost 515 nm laser, and the validity has been demonstrated. The Yb:YAG crystal with 10% concentration was 300 μm thickness and 10 mm in diameter. The four-pass optical coupling system was well designed with two spherical imaging mirrors (ϕ = 30 mm, R = 50 mm). Taking into account mode matching, the pump-spot radius in the laser crystal was calculated by LightTools software. The 2 × 2 × 1.5 mm³ BIBO crystal cutting at a type-I phase-matching direction of (θ, φ) = (166.8°, 90°) was employed. With 4.4 W incident power, the maximum output power of 14.3 mW at 515 nm was obtained without optimization of soldering technique, and the single-frequency phenomenon was first observed when the output power was 3 mW.     

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.