Tm,Ho双掺调Q激光系统理论与实验研究

本文针对Tm,Ho双掺的激光系统,利用速率方程理论,得出了激光各能级的反转粒子数分布规律.通过计算预测出了超过1 ms的时间有巨脉冲的光子输出,脉冲能量为88.4 mJ,脉冲宽度为426 ns.实验采用环形腔声光调Q,Tm,Ho:LuLF为激光介质,三向侧面抽运.自由运转和调Q状态的斜率效率分别为6.36%和2.9%.注入能量3.25 J时,自由运转激光能量103.2 mJ,调Q激光能量为30.3 mJ,对应光-光效率为3.17%,0.93%;注入能量3.5 J时,自由运转激光能量为129.3 mJ,调Q激光能量35.9 mJ,对应光-光效率为3.69%,1.02%.最大的动静比为32.8%.激光脉冲宽度为417.2 ns.如果环形腔能够单向运转,那么得到的激光能量和光-光转换效率都将增大一倍,与预测结果更加一致.     

1064nm纳秒激光脉冲激发的外腔式PbWO4拉曼激光器

研究了外腔式PbWO4拉曼激光器在纳秒脉冲抽运下的输出特性。利用主动调Q的Nd:YAG激光器产生的脉冲宽度为31.4ns,最大输出能量为200mJ的1064nm激光作为抽运源。拉曼激光谐振腔采用的是平凹腔设计。测量了输出的拉曼光脉宽与抽运能量的关系,分析了输出的拉曼光脉冲波形图和光谱图,测量了输出的拉曼光脉冲能量与抽运能量的关系,计算了转换效率与抽运能量的关系。当注入抽运光能量达到42mJ时,得到了一阶斯托克斯光脉冲的最大能量和转换效率分别为10mJ和24%,获得外腔式PbWO4拉曼激光器的一阶斯托克斯光脉冲波长为1177.6nm,典型的一阶斯托克斯光脉冲脉宽为20ns。     

Diode-side-pumped AO Q-switched Tm,Ho:LuLF laser

A diode-side-pumped Tm,Ho:LuLiF laser at 2-m wavelength obtained in a ring resonator and its amplification experiment are reported. At the maximum pump energy of 4.7 J available for the oscillator,the output energy per pulse for the oscillator decreases from 904 to 483 mJ in free running mode,and decreases from 106 to 68 mJ in Q-switched mode,with an increase of pump pulse repetition rate from 1 to 5 Hz. When considering the amplifier,99-mJ Q-switched output energy is achieved at 5-Hz repetition rate.     

Experimental investigation of pulse diodes side-pumped 2 μm Tm:YAG lasers

The free running and Q-switched operation of 2 μm Tm:YAG lasers side-pumped by pulse laser diodes were reported. In the free running mode the maximum output energies were 102.5 mJ at 1 Hz and 94.6 mJ at 10 Hz, respectively. With an acousto-optic modulator in the laser resonator, 21 mJ 2 μm Q-switched pulse was obtained, with a pulse width of about 330 ns. The dependences of the output energy and the efficiency on the laser resonator parameters were investigated.     

Yb:YAG power oscillator with high brightness and linear polarization

A diode-pumped Yb:YAG laser with a novel end-pumped zigzag slab architecture has been developed. This architecture provides uniform transverse pump profiles, conduction cooling of the laser crystal, mechanical robustness, and ready scalability to higher powers. At room temperature the laser emits 415 W of cw power with 30% optical conversion efficiency. An image-inverting stable resonator permits a high-brightness output of 252 W with linear polarization and an average M(2) beam quality of 1.45. Q-switched pulse energies of as much as 20 mJ and average Q-switched powers of as much as 150 W were obtained while M(2) was maintained at <1.5.     

Diode-pumped Q-switched Nd:GdVO4/KTP green laser formed with a flat–flat resonator

A diode-pumped acousto-optically Q-switched intracavity frequency-doubled Nd:GdVO₄/KTP green laser formed with a flat–flat resonator was demonstrated. 3.05 W of average green output power at pulse repetition frequency (PRF) of 40 kHz was obtained with an optical conversion efficiency of 18.4%, the effective intracavity frequency-doubling efficiency was 57%. At the incident pump power of 15 W, the shortest laser pulse occurred at PRF of 25 kHz with FWHM width of 14 ns, yielding the highest peak power of 7.44 kW; while the largest pulse energy of 0.14 mJ was achieved at PRF of 15 kHz.     

1.444 mm Nd:YAG激光器的实验研究

 在理论分析的基础上设计了直腔结构1.444 mm Nd:YAG激光器，并进行了实验研究。获得了1.444 mm激光输出，当泵浦能量为55 J时，其最高静态激光输出310 mJ。电-光转换效率为0.56%，斜效率为0.81%。并实现了1.444 mm调Q输出，脉冲输出能量18 mJ，脉宽150 ns。     

Diode-pumped high-efficiency high-brightness Q-switched ND:YAG slab laser

A high-efficiency diode-pumped Q-switched Nd:YAG oscillator designed for future spaceborne applications has been demonstrated and characterized. The laser is based on a side-pumped slab geometry and uses an unstable resonator with a radially variable-reflectivity output coupler. The laser provides an output pulse energy of 100 mJ at a 100-Hz repetition rate, with a near-diffraction-limited beam and an overall electrical optical efficiency exceeding 6%.     

A Highly Efficient SHG in CPM, Nd:YAG/LBO Laser

An energy conversion efficiency of 65.3% for second harmonic generation (SHG) from 1.06 μm to 0.53 μ m has been achieved by intracavity frequency doubling (IFD) in LiB 3O 5(LBO) crystal and a colliding pulse mode locked (CPM) Nd:YAG pulsed laser with a convex antiresonant ring (ARR) unstable resonator. For a fundamental wave with 20.2 mJ energy, 10 ps duration and a energy stability of 96.4%, a green output energy of 13.2 mJ was obtained. The energy conversion efficiency in IFD is much higher than that in extracavity frequency doubling (EFD) which is only 33.87%.     

外腔式SrWO4拉曼激光器的输出特性研究

研究了外腔式SrWO4拉曼激光器在ns脉冲抽运下的输出特性。利用主动调Q的Nd∶YAG激光器产生的脉冲宽度为11.7 ns,输出能量为80 mJ的激光作为抽运源,拉曼激光谐振腔采用平平腔,实验采用4片对一阶斯托克斯脉冲和二阶斯托克斯脉冲不同反射率的输出耦合镜,测量了输出能量与抽运能量的关系,计算了转换效率与抽运能量的关系。当输出耦合镜对一阶斯托克斯脉冲的反射率为39.9%时,实验得到一阶斯托克斯脉冲的最大能量和转换效率分别为23.9 mJ和36.2%,当输出耦合镜对一阶斯托克斯脉冲和二阶斯托克斯脉冲的反射率分别为80.5%和12.4%时,得到二阶斯托克斯脉冲的最大输出能量和转换效率分别为16.4 mJ和25.4%,典型的一阶斯托克斯脉冲和二阶斯托克斯脉冲的脉冲宽度分别为6.1 ns和5.8 ns。     

Room temperature efficient continuous wave and Q-switched operation of a Ho:YAP laser

We report the continuous wave and acousto-optically Q-switched operation of a Tm:YLF-pumped Ho:YAP laser at room temperature. Continuous wave output power of 6.8 W at 2118 nm was obtained under the incident pump power of 13.4 W, corresponding to a slope efficiency of 65.6% and a conversion efficiency of 50.7%. For the Q-switched mode, a maximum pulse energy of 1.28 mJ and a minimum pulse width of 31 ns at the repetition rate of 5 kHz were achieved, resulting in a peak power of 41.3 kW. In addition, the Ho:YAP laser was employed as a pumping source of ZGP optical parametric oscillator, the total average output power of which was 3.2 W at 4.08 and 4.41 μm with a slope efficiency of 69.5%, corresponding to the diode-to-mid-IR conversion efficiency of 9.0%.     

Ce3+∶LiCaAlF6紫外激光器的研究

报道了利用Nd∶YAG四倍频266 nm脉冲激光端面泵浦Ce∶LiCAF晶体，采用平凹谐振腔，输出296 nm波长紫外激光.当输出镜透过率为20％，入射泵浦能量为13.5 mJ时，获得最大输出激光脉冲能量为270 μJ，脉冲宽度为3.4 ns，输出激光峰值功率为79.4 kW，光－光转换效率为2%，斜效率为1.6％.     

MW peak power KTP-OPO-based “eye-safe” transmitter

We demonstrate MW-level, single resonance optical parametric oscillator, based on KTP Type-II crystal with noncritical phase-matching. The OPO is pumped by electro-optically Q-switched Nd:YAG slab laser providing 55?mJ of pulse energy. At the output, we achieved 28?mJ of signal pulse energy at 1.57?μm with 51% conversion efficiency, corresponding to 1.4?MW of peak power.     

High energy and high stability Cr:YAG passively Q-switched laser with convex-ARR unstable resonator

A convex-ARR (Anti-resonant Ring) unstable resonator was introduced in a Cr⁴⁺:YAG passively Q-switched Nd:YAG pulsed laser. There are two novel features in this cavity, one is the unstable resonator increasing output energy and improving laser mode; the other is the ARR structure efficiently enhancing the laser stability. A high energy and high stability Q-switched pulse with a single pulse energy of 85.6 mJ, a pulse width of 38 ns and an energy stability of 99.6% was obtained. The experimental results were analyzed well by using the mechanism of transient grating and the properties of the unstable resonator.     

Efficient continuous wave and Q-switched operation of a dual-end-pumped <Emphasis Type="Italic">c</Emphasis>-cut Tm:YAP laser

An efficient continuous wave (CW) and Q-switched c-cut Tm:YAP laser is reported in this letter. With the dual-end-pumped convex-concave resonator, CW output power up to 13.6 W at 1.99 μm was obtained under a total incident pump power of 50 W. The corresponding slope efficiency was 34.3% and conversion efficiency was 27.2%. The active Q-switched operation of the laser had an average output power of 12.5 W at 10 kHz pulse repetition frequency, with a minimum pulse width of 126 ns. With 6 kHz pulse repetition frequency, the maximum pulse energy of 1.6 mJ was obtained. In addition, using the Tm:YAP laser as a pumping source for gain-switched Cr:ZnSe laser, as much as 4 W output power in the wavelength range of 2.5–2.6 μm was obtained.     

Depolarization loss compensated resonator for electro-optic Q-switched solid-state laser

A novel laser resonator for compensating depolarization loss that is due to thermally induced birefringence in active rod is reported. As this new structure being applied to an electro-optic Q-switched LDA side-pumped Nd:YAG laser operating at a repetition rate of 1000 Hz, substantial reduction in depolarization loss has been observed, the output pulse energy is improved about 56% from that of a traditional resonator without compensation structure. With incident pump energy of 450 mJ per pulse, linearly polarized output energy of 30 mJ per pulse is achieved, the pulse duration is less than 15 ns, and the peak power of pulse is about 2 MW. The extinction ratio of laser beam is better than 10:1, and the beam divergence is 1.3 mrad with beam diameter of around 2.5 mm.     

LD连续泵浦Nd:YVO4声光调Q激光器

 利用半导体激光器（LD）连续单端泵浦Nd:YVO₄晶体，实现了声光调Q输出1 064nm的短脉冲。分析并用实验验证了不同透过率输出耦合镜及不同重复频率条件下，输出调Q脉冲能量、脉冲宽度及平均输出功率的规律。在泵浦功率为20.7W，重复频率为50kHz时，获得了最大平均输出功率为5.72W的脉冲，光 光转换效率为28%，斜效率为32.4%；在重复频率为10kHz时，最大单脉冲能量为0.286mJ，脉宽为22ns，峰值功率为13kW。     

环形腔2.05μm单谐振KTP晶体光参量振荡器研究

针对大气CO_2浓度探测差分吸收激光雷达的应用需求,采用稳定环形腔和模式匹配设计,搭建了一套单纵模1 064nm激光泵浦的单谐振KTP晶体光参量振荡器,获得高斜率转换效率、基横模的2.05μm波长纳秒激光脉冲输出.在8字形环形行波稳定腔中,将2块II类相位匹配KTP晶体以走离补偿方式放置,在20Hz重复频率下,当泵浦单脉冲能量达到11mJ时,获得了单脉冲能量为2.4mJ的2.05μm信号光输出,脉宽约24ns,斜率效率达到53%.2.05μm信号光光束质量因子在x、y方向分别为1.3和1.2.     

Diode end-pumped Q-switched high-power intracavity frequency-doubled Nd:GdVO4/KTP green laser

A diode-laser-array end-pumped acousto-optically Q-switched intracavity frequency-doubled Nd:GdVO₄/KTP green laser, formed with a three-mirror folded resonator, has been demonstrated. With 15 W of pump power incident upon the Nd:GdVO₄ crystal, a maximum average green output power of 3.75 W was obtained at 50 kHz of pulse repetition frequency, giving an optical conversion efficiency of 25%, whereas the effective intracavity frequency-doubling efficiency was determined to be 72%. At the incident pump power of 12.8 W, the shortest laser pulse was achieved at a pulse repetition rate of 10 kHz, the resulting pulse width, single pulse energy, and peak power were measured to be 35 ns, 108 μJ, and 3.1 kW, respectively. Received: 18 May 2000 / Published online: 20 September 2000     

二极管面阵侧泵浦Nd:YAG双板条激光器

叙述了二极管面阵侧泵浦双板条耦合单模模Ｑ开关激光器的研制。泵浦源为二极管面阵激光器,使用梯形波导板耦合系统,耦合效率达９０％,谐振腔为凸凹腔,全反射镜、的曲率半径为３．０ｍ的四面镜,输出镜为曲率半径３．０ｍ的可变反射率超高斯镜。激光器在１００Ｈｚ重复频率下,输出单脉冲能量１８．２３ｍＪ,脉宽为１５．２５ｕｓ,光束质量Ｍ２＜１．５具有平顶分布的超高斯光束。