26 mJ, 130 W Q-switched fiber-laser system with near-diffraction-limited beam quality

We demonstrate a Q-switched fiber laser system emitting sub-60 ns pulses with 26 mJ pulse energy and near-diffraction-limited beam quality (M2<1.3). In combination with a repetition rate of 5 kHz, a corresponding average output power of 130 W is achieved. This record performance is enabled by a large-pitch fiber with a core diameter of 135 μm. This fiber allows for effective single-mode operation with mode field diameters larger than 90 μm even at average output powers exceeding 100 W.     

Passively Q-switched Tm:YLF laser

Stable passive Q-switching of a Tm: LiYF4 laser is obtained using polycrystalline Cr2+: ZnS as a saturable absorber. The achieved maximum pulse energy of 0.9 mJ and peak power of 65 kW for a pulse duration of ～14 ns represent substantial improvement and highest values for a passively Q-switched diode-pumped Tm laser operating at ～1.9 μm.     

Passively Q-switched Tm,Ho:LuLiF4 laser with near constant pulse energy and duration

A compact diode-pumped passively Q-switched Tm,Ho:LuLiF₄ laser with a Cr:ZnS saturable absorber is demonstrated for the first time. The maximum average output power of 74 mW is achieved at the absorbed pump power of 1.5 W, and the threshold power is only 0.68 W. The laser operates at the wavelength of 2,055 nm and produces pulses with near constant duration of 1.2 μs and pulse energy of 13 μJ at the pulse repetition frequency from 1 to 5.2 kHz. The stable long-pulse laser can be used in laser lidar systems for accurate wind velocity measurements.     

Passively Q-switched diode-pumped Tm,Ho:LuVO_4 laser with a black phosphorus saturable absorber

We presented a passively Q-switched(PQS) diode-pumped c-cut Tm, Ho:LuVO_4 laser with a black phosphorus saturable absorber for the first time.Under PQS mode, an average output power of 0.86 W and a peak power of 2.32 W were acquired from the Tm, Ho:LuVO_4 laser with the pump power of 14.55 W, corresponding to a pulse width of 2.89 μs,a pulse repetition rate of 71.84 kHz, and a pulse energy of about 6.70 μJ.     

Efficient passively Q-switched Yb:LuAG microchip laser

An efficient passively Q-switched Yb:LuAG microchip laser with Cr4+:YAG as saturable absorber was demonstrated for the first time to our knowledge. Slope efficiencies of 40% and 28% were measured for the initial transmission of Cr4+:YAG, T(0)=95% and 90%, respectively. Laser pulses with a pulse energy of 19 microJ and a pulse width of 610 ps at the repetition rate of 12.8 kHz were achieved for T(0)=90%; the corresponding peak power of over 31 kW was obtained. The lasers oscillated at two or three longitudinal modes owing to the broad emission spectra of Yb:LuAG and mode selection by Cr4+:YAG thin plate acting as an intracavity etalon.     

522 W average power, spectrally beam-combined fiber laser with near-diffraction-limited beam quality

We report a three-channel, spectrally beam-combined (SBC), 1 mum fiber laser that produces 522 W of average power with near-diffraction-limited (M2 ~ 1.2) beam quality. The laser features a SBC power combining efficiency of 93%, versatile master-oscillator, power-amplifier fiber channels with up to 260 W of narrow-band, polarized, and near-diffraction-limited output that is tunable over nearly the entire 1 micro m Yb(3+) gain bandwidth, and excellent prospects for significant power scaling. To our knowledge, these results represent the highest beam quality and average power achieved to date for a beam-combined fiber laser system.     

基于单壁碳纳米管调Q锁模低阈值Tm,Ho:LiLuF_4激光器

采用垂直生长法制作的单壁碳纳米管作为可饱和吸收体,结合特殊的低阈值谐振腔设计,首次在Tm,Ho:LiLuF_4全固态激光器中实现了低阈值自启动被动调Q锁模运转.以波长可调的掺钛蓝宝石固体激光器作为抽运源,选用1.5%,3%和5%的输出耦合镜,获得了出光阈值低至52,59和62mW的连续光输出.采用3%输出耦合镜,获得了阈值低至250mW的稳定调Q锁模脉冲输出,调Q包络的脉宽为2μs,调Q包络下锁模脉冲重复频率178.6MHz,最大输出功率154mW,最大的单脉冲能量为0.86nJ,调制深度接近100%.     

Diode-pumped Q-switched Tm:LuAG ring laser operation at room temperature

2-μm lasers with high pulse energy and long pulse width of hundreds of nanoseconds are needed urgently in the accurate wind velocity lidar systems. This paper presented the acoustic-optical Q-switched Tm:LuAG laser performance in a pulsed-laser-diode end-pumping figure-eight ring resonator structure. Pulse energy and pulse width are investigated with the increasing of the incident pump energy at different repetition rate operation. Maximum energy of 3.3 mJ with the pulse width of 199 ns and 1.8 mJ with pulse width of 293 ns are obtained at the repetition rate of 20 and 50 Hz, respectively. Under Q-switched operation, the peak output wavelength is 2.022 μm at all time, and the beam quality factors are lower than 2 times diffraction-limited measured by a knife-edge traveling method.     

Passively Q-switched Nd3+:YAG laser with corner cube

A passively Q-switched Nd3+:YAG laser with corner cube is theoretically and experimentally studied. We analyze the polarization variation in cavity and simulate the peak power, pulse energy and pulse width changed with the rotation angle of corner cube numerically. An experiment is made to verify the theoretical results. With rotating the angle of corner cube about the axis the variation range of peak power is 1.77 MW (from 10.36 to 8.59 MW), and that of pulse energy is 14.9 mJ (from 159.5 to 174.4 mJ), the fluctuation of pulse width is 2.95 ns. The experimental results agree with the theoretical analysis to the extent of variation rules. The most dynamic to static energy ratio of 62.5% is achieved.     

Operation of electro-optically Q-switched Nd:LuAG laser at 1064 nm

We present the operation of a diode-pumped high-power electro-optically Q-switched 4 W Nd:LuAG laser operating at 1064 nm. At an absorbed optical power of 20 W, the laser described provides a maximum output of 3.5 W average power at a repetition rate of 50 Hz. The output varies up to a factor of 1.3% for about 1 h operation with a peak power of 280 kW, with the laser beam quality in the TEM00 mode.     

基于氧化石墨烯的瓦级调Q锁模Tm:LuAG激光器

在Tm:LuAG全固态激光器中实现了以氧化石墨烯可饱和吸收体为锁模启动元件的瓦级被动调Q锁模运转.本实验装置以可调谐掺钛蓝宝石激光器作为泵浦源,测得Tm:LuAG固态激光器出光阈值最低为325mW,当吸收抽运功率达到3420 mW时,进入稳定的调Q锁模运行状态.当抽运功率达到8.1 W时,对应的最大输出功率为1740 mW,中心波长为2023 nm,重复频率为104.2 MHz,最大单脉冲能量为16.7 nJ,调制深度接近100%.     

Graphene passively Q-switched Ho:YAG ceramic laser

We report on the first graphene passively Q-switched Ho:YAG ceramic laser with central wavelength of 2,097 nm. Stable pulses of 28–64 kHz repetition rate and 2.6–9 μs pulse widths were generated under 1,907 nm thulium fiber laser pumping. Maximum average power of 264 mW with 9.3 μJ pulse energy was obtained under 3.27 W of pump power.     

Passively Q-switched Self-frequency Doubling NYAB laser with GaAs Saturable Absorber

By using a passive Q-switch with GaAs saturable absorber, the Q-switched self-frequency doubling NYAB laser at 0.531μm has been successfully realized. The pulse width and the single pulse energy are measured. The numerical solutions of the coupling wave rate equations are in agreement with the experimental results.     

Passively Q-switched diode-pumped Raman laser with third-order Stokes eye-safe oscillation

We demonstrate a passively Q-switched all-solid-state laser system with intracavity Raman frequency conversion to the eye-safe spectral region. Laser oscillation at the 1.064 μm wavelength with a pulse repetition rate of several kilohertz was provided by a Nd:YAG crystal and a Cr:YAG passive absorber. Third Stokes oscillations at the 1.599 and 1.494 μm wavelengths were obtained in Ba(NO₃)₂ and PbWO₄ crystals with output pulse energies of 5 μJ and 6 μJ, respectively. The results of the numerical simulation of the pulse dynamics are in good agreement with the experimental data.     

Passively Q-switched Self-frequency Doubling NYAB laser with GaAs Saturable Absorber

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氧化石墨烯被动调Q掺铒光纤激光器

报道了基于氧化石墨烯的被动调Q掺铒光纤激光器。激光器采用环形腔结构,调Q器件为自制的氧化石墨烯可饱和吸收镜。泵浦功率在81~505 mW范围内时,得到了重复频率68~124 kHz的稳定的调Q脉冲输出,脉宽为0.47~1.60 s。由于泵浦功率限制,激光器最大输出功率为10 mW, 相应单脉冲能量为80.6 nJ。此种基于氧化石墨烯可饱和吸收体的被动调Q光纤激光器体积小、成本低廉、结构简单、稳定性高、光束质量高,具有广阔的应用前景。     

Passively Q-switched a-cut Nd:GdVO4 self-Raman laser with Cr:YAG

A passively Q-switched a-cut Nd:GdVO₄ self-Raman solid-state laser with Cr:YAG saturable absorber was firstly demonstrated. The first Stokes at 1173 nm was successfully obtained. At the maximum incident pump power, the pulse width was about 1.8 ns and the repetition rate was 27.5 kHz. 586.5 nm yellow laser output was also realized by use of an LBO frequency doubling crystal.     

516 mW,nanosecond Nd:LuAG laser Q-switched by gold nanorods

Q-switched operation of an Nd:LuAG laser using gold nanorods(GNRs) as the saturable absorber(SA) is reported, which also produces the highest average power among the nanosecond Nd-doped Q-switched lasers by GNRs-based SA. The applied GNRs are prepared using a seed-mediated growth method and then dropped onto the quartz substrate to fabricate the SA. The average power of the Q-switched laser is 516 mW with the shortest pulse duration of 606.7 ns and the repetition rate of 265.1 kHz.     

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.