2 μm波段半导体可饱和吸收镜被动调Q光纤激光器

基于半导体可饱和吸收镜和光纤光栅实现了稳定的2 m波段被动调Q光纤脉冲激光器,输出激光的中心波长为1958.2 nm。随着泵浦功率的增加,输出脉冲的重复频率不断增加,而对应脉冲的宽度不断减小。输出脉冲重复频率的变化范围为20～80 kHz,脉冲宽度的变化范围为490 ns～1 s。当泵浦功率为1.3 W时,调Q光纤激光器的最大平均输出功率为91 mW,脉冲重复频率为80 kHz,脉冲宽度为490 ns,对应的最大单脉冲能量约为1.14 J。     

高峰值功率中红外2.8μm脉冲光纤激光器

采用中心波长为975nm半导体激光器泵浦高掺铒氟化物双包层光纤Er∶ZBLAN,并在谐振腔内插入主动调Q元件,获得了工作频率为1~10kHz的2.8μm激光主动调Q脉冲输出.在工作频率为10kHz条件下,获得了最大单脉冲能量为134.5μJ、脉宽为127.3ns、峰值功率为1.1kW的脉冲输出.     

100 W全光纤声光调Q光纤激光器实验研究

 报道了一台全光纤结构主振荡功率放大(MOPA)型掺镱脉冲光纤激光器,以光纤光栅为腔镜,光纤型声光调Q的光纤激光器为种子源,通过两级掺镱双包层光纤放大器实现功率放大。对声光调Q的光纤激光器输出特性进行了研究,比较了不同泵浦波长、不同重复频率对激光输出功率和脉冲宽度的影响,并实现了最短脉冲宽度25 ns、单脉冲能量45 μJ的脉冲激光输出。在重复频率50 kHz时,对脉冲宽度130 ns、平均功率0.6 W的种子光进行放大,得到了平均功率102.5 W、脉冲宽度约240 ns的激光输出。     

LD泵浦Nd∶GdVO4/GaAs被动调Q激光器研究

报道了采用大功率半导体激光器端面泵浦Nd∶GdVO4晶体,利用GaAs晶片兼作饱和吸收被动调Q元件和输出耦合镜,实现了1.06 μm激光的被动调Q运转.在泵浦功率为13.9 W时,获得最高平均输出功率为3.6 W,脉冲宽度为252 ns,单脉冲能量为27 μJ以及峰值功率为107 W的激光脉冲.     

LD泵浦Nd∶LuVO4/Cr4+∶YAG被动调Q激光器

采用大功率半导体激光器端面泵浦Nd∶LuVO4晶体，利用Cr4+∶YAG晶体作为可饱和吸收元件，实现了1.06 μm激光的被动调Q运转.在泵浦功率为19.1 W时，获得最高平均输出功率为4.58 W，脉冲宽度为84 ns，单脉冲能量为36.6 μJ以及峰值功率为436.2 W的激光脉冲.     

12 W Q-switched Er:ZBLAN fiber laser at 2.8 μm

A diode-pumped, actively Q-switched 2.8 μm fiber laser oscillator with an average output power of more than 12 W has been realized through the use of a 35 μm core erbium-doped ZBLAN fiber and an acousto-optic modulator; to our knowledge, this is the first 3 μm pulsed fiber laser in the 10 W class. Pulse energy up to 100 μJ and pulse duration down to 90 ns, corresponding to a peak power of 0.9 kW, were achieved at a repetition rate of 120 kHz.     

LD泵浦的声光调Q高重复率Nd∶GdVO4激光器

报道了利用LD泵浦、1.06 μm声光调Q准连续Nd∶GdVO4激光器的输出特性.当泵浦功率为4.15 W,重复率为40 kHz时,获得的最大平均输出功率为1.46 W,光-光转换效率为35.1%,斜效率为44.2%.在重复率为10 kHz时,获得了最短脉宽24 ns, 最大单脉冲能量为63.2 μJ,相应峰值功率为2.62 kW.     

220 μJ monolithic single-frequency Q-switched fiber laser at 2 μm by using highly Tm-doped germanate fibers

We report a unique all fiber-based single-frequency Q-switched laser in a monolithic master oscillator power amplifier configuration at ~1920 nm by using highly Tm-doped germanate fibers for the first time. The actively Q-switched fiber laser seed was achieved by using a piezo to press the fiber in the fiber Bragg grating cavity and modulate the fiber birefringence, enabling Q-switching with pulse width and repetition rate tunability. A single-mode polarization maintaining large core 25 μm highly Tm-doped germanate fiber was used in the power amplifier stage. For 80 ns pulses with 20 kHz repetition rate, we achieved 220 μJ pulse energy, which corresponds to a peak power of 2.75 kW with transform-limited linewidth.     

外腔式宽调谐被动调QNd:YVO_4/PPMgLN光学参量振荡器

报道了一个低阈值宽调谐、被动调Q、单谐振掺MgO的周期性极化铌酸锂晶体(PPMgLN)光学参量振荡器。利用被动调Q的Nd:YVO4激光器作为泵浦源,采用外腔结构,在室温下,实现了PPMgLN晶体的准相位匹配光学参量振荡。光参量振荡的阈值仅为0.27W(单脉冲能量4.5μJ、脉宽35ns);在泵浦光为1.35W(脉冲能量8.2μJ、脉宽35ns),PPMgLN周期为31μm时,获得了161.9mW,3.202μm脉冲激光输出;同时获得了98.5mW的1.594μm信号光输出,总的光光转化效率达到19.3%。通过改变晶体的周期,实现了闲频光3.13～4.19μm,信号光1.43～1.65μm的宽带可调谐激光输出。     

Acousto-optic Q-switched self-frequency-doubling Er:Yb:YAl3(BO3)4 laser at 800 nm

Actively Q-switched self-frequency-doubling laser at 800 nm was first reported in an Er:Yb:YAl3(BO3)4 crystal by using an acousto-optical modulator. At incident pump power of 16 W and pulse repetition frequency of 1 kHz, 1600 nm fundamental pulse laser with energy of 130 μJ and width of 170 ns, and self-frequency-doubling 800 nm pulse laser with energy of 20 μJ and width of 96 ns were respectively achieved in a hemispherical resonator end-pumped by a 970 nm laser diode. Pulse characteristics of fundamental and self-frequency-doubling lasers at different pulse repetition frequencies were also investigated.     

Passively Q-switched 1.32-μm Nd:YAG laser with a V:YAG saturable absorber

By using a new saturable absorber V³⁺:YAG, a flash-lamp-pumped passively Q-switched Nd:YAG laser at 1.32 μm has been realized. The single-pulse energy and the pulse width of the output laser versus the pump energy are measured. With a cavity length of 440 mm and a pump energy of 43.4 J, the obtained single-pulse output energy and pulse width are 10 mJ and 86.9 ns, respectively, corresponding to a peak power of 115 kW.     

Tm(3+)/Ho(3+) codoped tellurite fiber laser

Continuous-wave and Q-switched lasing from a Tm(3+)/Ho(3+) codoped tellurite fiber is reported. An Yb(3+)/Er(3+)-doped silica fiber laser operating at 1.6 microm was used as an in-band pump source, exciting the Tm(3+) ions into the (3)F(4) level. Energy is then nonradiatively transferred to the upper laser level, the (5)I(7) state of Ho(3+). The laser transition is from the (5)I(7) level to the (5)I(8) level, and the resulting emission is at 2.1 microm. For continuous wave operation, the slope efficiency was 62% and the threshold 0.1 W; the maximum output demonstrated was 0.16 W. Mechanical Q switching resulted in a pulse of 0.65 microJ energy and 160 ns duration at a repetition rate of 19.4 kHz.     

Study of passive Q-switching for flash-lamp-pumped 1.34-μm Nd:GdVO4 laser

The static laser performance of a-growth Nd:GdVO4 crystal (a-cut, 4 × 4 × 25 (mm)) at 1.34μm pumped by flash-lamp is investigated with different transmissions of output couplers. With the output coupler transmission of T = 30%, the static output energy of 148 mJ is obtained when the pump energy is 35.2 J,and the corresponding electric-optical conversion efficiency is 0.42%. The Q-switched output of lasers with the output wavelength ranging from 1.3 to 1.6 μm can be realized by using Co2+ :LaMgAl11O19 (Co:LMA)as saturable absorber. A flash-lamp-pumped, passively Q-switched Nd:GdVO4 laser with Co:LMA as saturable absorber is demonstrated in plano-concave laser cavity. With the cavity length of 16.3 cm and pump energy of 19.8 J, the single-pulse output energy, pulse width, and peak power are obtained to be 4m J, 80 ns, and 5 × 104 W, respectively.     

Acousto-optic Q-switched laser performances of Er3+:Yb3+:LuAl3（BO3）4 crystal at 1.5-1.6 μm

Diode-pumped acousto-optic Q-switched pulse laser at 1.5-1.6 μm is obtained in an Er3+:Yb3+:LuAl3 (BO3)4 crystal. Single-pulse laser operation with slope efficiency of 14% and threshold of approximately 100 mW is realized at an average absorbed pump power of 314 mW and repetition frequency of 20 kHz. Output pulse energy is 67 μJ. The effects of pulse repetition frequency, absorbed pump power, and duty cycle on the wavelength and pulse profile of the Q-switched Er3+:Yb3+:LuAl3(BO3)4 laser are also investigated.     

Q-switched operation of an in-band-pumped Ho:LuAG laser with kilohertz pulse repetition frequency

We report continuous-wave (CW) and repetitively Q-switched operation of an in-band-pumped Ho:LuAG laser at room temperature. End-pumped by a Tm:YLF solid-state laser with emission wavelength of 1.91 μm, the CW Ho:LuAG laser generated 5.4-W output at 2100.7 nm with beam quality factor of M ²～1.03 for an incident pump power of 14.1 W, corresponding to slope efficiency of 67% with respect to absorbed pump power. Up to 1.5-mJ energy per pulse at pulse repetition frequency (PRF) of 3 kHz and 4.5-W average power with FWHM pulse width of 28 ns at 5 kHz were demonstrated in repetitively Q-switched operation.     

Passively Q-switched microchip Er, Yb:YAl3(BO3)4 diode-pumped laser

We report, for the first time to our knowledge, a diode-pumped cw and passively Q-switched microchip Er, Yb:YAl(3)(BO(3))(4) laser. A maximal output power of 800 mW at 1602 nm in the cw regime was obtained at an absorbed pump power of 7.7 W. By using Co(2+):MgAl(2)O(4) as a saturable absorber, a TEM(00)-mode Q-switched average output power of 315 mW was demonstrated at 1522 nm, with pulse duration of 5 ns and pulse energy of 5.25 μJ at a repetition rate of 60 kHz.     

Continuous-wave and Q-switched laser operation of Nd:Gd0.18Y0.82VO4 mixed crystal

Efficient continuous-wave (cw), passively Q-switched, and actively Q-switched laser operations are demonstrated with a mixed vanadate crystal of Nd:Gd_0.18Y_0.82VO₄ under diode pumping. In a cw operation, an output power of 8.25 W is obtained at a maximum available incident pump power (P_in) of 15 W, with a slope efficiency of 56%. Using a Cr⁴⁺:YAG crystal of initial transmission of 62% as the saturable absorber for Q-switching, an average output power of 3.05 W is generated at pulse repetition frequency (PRF) of 16.7 kHz when the laser is pumped with the same maximum P_in. The pulse energy, pulse duration, and peak power are 183.3 μJ, 6.0 ns, and 30.6 kW, respectively. When actively Q-switched by an acousto-optic modulator, the laser produces an average output power of 5.5 W at PRF of 30 kHz with 16.2 W of pump power incident upon the laser crystal. The pulse energy, duration, and peak power are measured to be 183 μJ, 10.5 ns, and 17.5 kW, respectively.     

一种基于增益调制技术的全光纤化脉冲Yb光纤激光器

以波长为975 nm的半导体激光器作为泵浦源,周期性地脉冲泵浦一个包含Yb掺杂光纤和光纤光栅对的Yb光纤激光器,实现了基于增益调制技术的全光纤化高功率Yb光纤激光器的稳定脉冲输出.在50 kHz重频下,采用20 W的泵浦功率和2.4 μs的泵浦脉冲宽度,获得了1 060 nm波长脉冲宽度仅100 ns的稳定脉冲激光输出,单脉冲激光能量约为20 μJ.以此作为脉冲激光种子进行功率放大,获得了性能稳定的全光纤结构高功率脉冲激光输出,放大后单脉冲能量超过200 μJ,激光放大器斜率效率达到60%.     

6.5-ns actively Q-switched Nd:YVO_4 laser operating at 1.34 μm

With a plano-concave cavity,diode-pumped continuous-wave(CW) and actively Q-switched Nd:YVO4 laser operating at 1.34 μm is demonstrated.Maximum CW output power of 4.76 W and Q-switched average output power of 2.64 W are obtained with output coupler(transmission T = 3.9%).For the Q-switching operation,the theoretically calculated pulse energy and pulse width,with a pulse repetition frequency(PRF) range of 5-40 kHz,coincide with the experimental results.With a T = 11.9% output coupler,the maximum peak power of 24.3 kW and minimum pulse width of 6.5 ns are obtained when the PRF is 10 kHz.To the best of our knowledge,this is the shortest actively Q-switched pulse duration ever obtained in a 1.3-μm Nd-doped vanadate laser.     

Nd:YVO4声光调Q腔内倍频457 nm蓝光激光器

脉冲蓝光激光器在水下探测、水下通信和遥感方面有着重要的应用前景。根据高斯光束传输的ABCD矩阵,设计了对热效应不灵敏的Z型谐振腔。利用808 nm激光二极管(LD)端面抽运Nd:YVO4晶棒,在室温下实现了4F3/2→4I9/2准三能级激光谱线跃迁。通过声光调Q和LBO腔内倍频,获得了稳定的高重复频率、高峰值功率457 nm蓝光激光输出。当抽运功率为30 W时,在重复频率为10 kHz下,获得最大单脉冲能量为56 μJ ,脉冲宽度为217 ns,峰值功率达258 W; 在重复频率为20 kHz下,获得最大平均功率为760 mW,脉冲宽度为261 ns,峰值功率为146 W。在最大平均输出功率下测量了脉冲457 nm蓝光激光器的功率稳定性,20 min之内其最大不稳定度小于2%。