增益调制高重频脉冲光纤激光器实验研究

采用脉冲泵浦方案,研制出了基于增益调制技术的全光纤结构高重频脉冲激光器。采用电路直接调制的激光二极管作为泵浦源,双包层光纤作为增益介质,构造了光纤光栅选模的线形腔结构。实验中通过调整泵浦光脉冲宽度和光纤激光器谐振腔长度,得到了稳定的高重频脉冲。在100kHz重复频率下,采用21W的峰值泵浦功率和2.5μs的泵浦脉冲宽度,获得了1.06μm波长,脉冲宽度247ns的稳定脉冲激光输出。脉冲峰值功率一致性好,平均功率长期功率稳定性为2%。观察并分析了由于纵模拍频在脉冲包络上产生的次脉冲特性。通过一级放大实现89.6 W输出。     

脉冲单频Nd:YVO4激光器及其倍频输出特性研究

为了研制激光干涉成像所需的主振荡功率放大(MOPA)结构脉冲单频激光器,本文完成MOPA激光器的种子源即声光调Q脉冲单频1 064 nm激光器的特性研究,同时完成种子源腔外倍频绿光特性研究。脉冲单频激光器采用声光调Q模块实现脉宽约20 ns的1 064 nm脉冲激光输出,采用环形腔设计并采用一组不同厚度的标准具实现单纵模运转。实验研究基频1 064nm和倍频532 nm激光脉冲的线宽,得出在全脉宽范围内都具有较高时间相干性的结论。实验分别获得脉宽约28 ns峰值功率约6.5 kW的1 064 nm脉冲单频激光和脉宽约20 ns、峰值功率约0.5 kW的532 nm脉冲单频激光,腔外倍频效率为5.6%。实验同时也验证了腔外倍频的激光脉宽压缩效应。     

斩波法在激光微能量计标定中的应用

针对激光微能量测量的问题,提出一种激光微能量计标定新方法与装置。研究内容包括使用稳功率连续激光作为光源,通过基于斩波的脉冲发生器组件产生微能量的脉冲激光,分别使用脉冲宽度测量组件与功率测量组件进行采集、软件分析,计算微能量值及通过比对给出待标定能量计的修正系数,计算机自动控制。结果表明,该方法获得的脉冲激光波形稳定,脉冲宽度测量不确定度为0.08%,激光功率测量不确定度为0.25%,实现了对0.1 pJ～1 mJ的激光能量进行准确复现和传递。     

基于ANSYS的脉冲激光辐照石英玻璃的温度场数值模拟

采用有限元仿真软件ANSYS 12.0对脉冲功率激光辐照石英玻璃建立了热力学模型,对其表面温度场进行了数值模拟,得到了在不同激光功率密度下的瞬态温度场分布,并对模拟结果进行了分析和研究,为激光辐照石英玻璃实验提供依据.     

Entwicklung leistungsfähiger Stickstofflaser mit abgeschmolzenem Laserrohr

For an increase of the laser pulse energy from longitudinally excited multiple electrodes tubes, experiments and model calculations have been accomplished. A variation of the electrode spacing in the laser tube has shown, that a maximum pulse energy could be achieved with about 40 mm electrode spacing. If barium titanat capacitors with a dielectric constant of 10000 in the pulse forming unit were applied, a voltage pulse transform occured enabling an increase of the laser power up to 50%. With a sealed off operated laser tube of 100 cm active length, a laser peak power of 600 kW and a pulse duration of 10 ns could be achieved. A tube with 200 cm active length generated a pulse power of 1.2 MW. The decrease of laser pulse energy with increasing pulse repetition rate can be explained by the decrease of impulse breakdown voltage. For an increase of the lifetime of laser tubes, appropriate technologies for the production of the tube have been developed.     

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侧面泵浦电光调Q532nm脉冲激光器

 为了实现高可靠、窄脉宽、高峰值功率激光输出,采用侧面泵浦技术和电光调Q技术,设计出一种激光二极管侧面泵浦电光调Q全固态绿光激光器。采用结构简单、紧凑的平-平腔设计,其端镜和输出镜均为平面镜,获得较稳定的侧面泵浦Nd∶YAG腔外倍频KTP脉冲绿光激光输出。当泵浦电流为120A,重复频率为600Hz时,获得脉冲绿光的最高输出平均功率为3.62W,1064nm到532nm的转换效率为15.3%,其脉宽为21ns,峰值功率为300kW, 单脉冲能量为6.01mJ。实验结果表明：该激光器稳定性可靠,输出激光脉宽较窄、峰值功率高。     

Single-frequency linearly-polarized 1083?nm all fiber nanosecond laser

Single-frequency linearly-polarized 1083?nm all fiber nanosecond master-oscillator power amplifier laser system is demonstrated. A ring laser, whose key components are one saturable absorber and two polarization controllers, delivers a single-frequency continuous wave laser. Using an electro-optic modulator as the modulator, the pulse laser seed is obtained by modulating the CW laser. By amplifying the pulse seed to the average power of 61.6?W in three stages, a single-frequency linearly-polarized laser with pulse duration of 16?ns, repetition rate of 10?MHz and pulse energy of 6.16???J is obtained. No nonlinear effect is observed in our experiment. Higher output power can be obtained by increasing LDs of the main amplifier.     

基于精确延时控制的脉冲激光功率合成研究

介绍了脉冲固体激光器时域上的功率合成原理。为了实现多台脉冲固体激光器时域上的高精度功率合成,通过分析影响多台激光器之间时域上的同步合成效率的因素,采用了负反馈精确延时的控制方式对脉冲激光器出光时间进行精确控制。通过仿真和实验结果,验证了脉冲固体激光器功率合成方法的可行性,实现了三台激光器精度小于1ns的高精度激光功率合...     

高精度激光微能量校准技术研究

利用斩波器将连续激光斩波成为脉冲宽度s量级重频脉冲激光,利用选单器将重频脉冲激光转变成单脉冲激光,从而实现变连续激光为单脉冲激光。由陷阱探测器测量连续激光的输出功率,高速APD、高增益PIN探测器作为波形探测器测量脉冲激光波形,并通过示波器对脉冲宽度进行测量。依据测量得到的功率和波形就可得到脉冲激光能量,从而实现了0.2 pJ激光微能量的测量和校准,通过不确定度分析,该装置的pJ激光能量测量不确定度达到了0.42%。     

A diode-pumped linear intracavity frequency doubled Nd:YAG rod laser with 40 ns pulse width and 73 W green output power

We analyzed a linear cavity for intracavity frequency doubling of a diode-pumped acousto-optic Q-switched Nd:YAG rod laser, and showed that a green laser beam with a short pulse width can be generated efficiently. A green laser output power of 73 W corresponding to the 83.9% of maximum IR output power was obtained with a 40 ns pulse width at a 10 kHz repetition rate. A green output power of 40 W with a 35 ns pulse width was measured at a 5 kHz repetition rate. Minimum laser pulse width of approximately 32 ns was obtained around 1 kHz repetition rate for both green and IR laser beams.     

High-energy soliton pulse generation with a passively mode-locked Er/Yb-doped multifilament-core fiber laser

We report the generation of high-energy short pulses from a mode-locked erbium/ytterbium-doped large-mode-area multifilament-core fiber laser operating in the purely anomalous dispersion regime. The self-starting fiber laser emits 400 mW of average output power at a pulse repetition rate of 44 MHz, corresponding to a pulse energy of 9.1 nJ. The laser produces near transform-limited output pulses with pulse duration of 1.6 ps, corresponding to 5 kW peak power. This new type of low-nonlinearity fibers demonstrates the power and energy scaling potential of fiber-based short pulse lasers in the eye-safe region.     

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%.     

LD-pumped passively Q-switched red laser at 660 nm

A laser diode (LD) pumped Nd:YAG red pulse laser at 660 nm was presented by V:YAG passively Qswitching and LBO intracavity frequency doubling. With 1.6-W incident pump power, average output power of 46-mW, pulse duration (FWHM) of 23.3 ns, pulse repetition rate of 21.6 kHz, peak power of 91.4 W, and single pulse energy of 2.13μJ were obtained. The beam quality factor M2 was less than 1.2. The fluctuations of pulse energy and repetition rate were less than 3% in 4 hours. The pulsed laser at 660 nm is expected to be used as the pump source of Cr3+:doped crystal to obtain the gain-switched tunable laser.     

同步泵浦PML飞秒激光研究

采用CW锁模YAG倍频激光器同步泵浦PML飞秒染料激光器,产生了平均脉宽约55fs、功率为15mW的光脉冲。文章在理论和实验上还研究了同步泵浦飞秒激光脉冲产生技术。     

高功率激光器电光调Q技术研究

通过分析激光速率方程得出增加初始态粒子反转数与阈值态粒子反转数比值(Ni/Nt),可以提高激光峰值功率,减小激光脉冲建立时间.采用双Q开关技术有效地抑制自激振荡,提高了Ni/Nt比值.设计了触发管高压脉冲发生电路,产生下降沿很快的高压脉冲信号,提高了Q开关速度,从而使得激光输出峰值功率达50 MW,效率达1.37%,对提高固体激光器的峰值功率与效率具有参考价值.     

脉冲宽度对云雾回波的影响研究

云雾后向散射会产生引发激光引信虚警的回波信号.基于蒙特卡罗法,对云雾散射回波进行了模拟仿真,并定量给出了云雾散射回波的波形、波峰位置、脉宽和峰值功率随发射脉冲宽度的变化规律.研究结果表明,回波峰值功率随着发射脉宽的增大而增大,且当发射脉宽增大到50ns后趋于饱和,峰值功率将不随脉冲宽度的变化而变化;脉冲展宽的程度随发射脉宽的增大而减弱;发射脉宽对云雾散射回波波峰位置的影响较小.给出的回波信号模拟仿真结果可以为窄脉冲激光引信的目标识别以及探测阈值和脉冲宽度等参量的优化设计提供依据.     

Diode-pumped Q-switched Nd:Y<Subscript>0.5</Subscript>Lu<Subscript>0.5</Subscript>VO<Subscript>4</Subscript> laser double-modulated with an acousto-optic modulator and Cr<Superscript>4+</Superscript>:YAG saturable absorber

A diode pumped Nd:Y_0.5Lu_0.5VO₄ pulse laser modulated with an acousto-optic (AO) Q-switcher and Cr⁴⁺:YAG saturable absorber is first demonstrated in this paper. The laser is shown to generate shorter pulse width than AO Q-switched laser alone, and have a higher peak power and single pulse energy than passively Q-switched laser with only Cr⁴⁺:YAG. A laser pulse width of 6.16 ns and a peak power of about 43.83 kW are achieved at the incident pumping power of 14.09 W.     

Diode-laser pumped high-power and actively mode-locked Nd:YLF laser with fast switching

In an actively mode-locked laser, self-phase modulation can make pulse shorter at the expanse of causing instability at high pumping power. Using fast switching on the acousto-optic modulator, we can generate an actively mode-locked pulse train with shorter pulse width and higher average power than that driven by a sinusoidal signal. A 9-ps pulse train was generated in a mode-locked laser with an average power of 600 mW whose power level, to our knowledge, is the highest for diode-pumped and mode-locked Nd:YLF lasers.     

基于光纤中SBS相位共轭的自调Q光纤激光器

分析了利用光纤中的受激布里渊散射(stimulated Brillouin scattering,SBS)相位共轭效应进行激光腔内调Q,产生ns量级脉冲激光的原理,并对利用该效应产生的激光脉冲波形和脉冲形成过程进行了数值模拟,得到的脉冲波形与SBS相位共轭反射率随时间变化曲线基本一致,表明利用光纤中的SBS相位共轭作用调Q具有可行性.据此,对采用单模光纤(single-mode fiber,SMF)作为SBS池的Er³⁺掺杂调Q光纤激光器进行实验研究.当单模光纤长度为1.5 m时,在45 mW的光抽运功率下得到脉宽约2.6ns,脉冲周期58.23ns,平均功率7.35mW的激光脉冲.进一步的研究表明:激光器中相位共轭镜的形成与SBS介质长度有关,SBS介质过长,斯托克斯线之间无固定的相位关系,不能形成相干叠加,SBS相位共轭腔不能形成;SBS介质过短,腔内正交偏振模光子寿命的改变使脉冲出现双峰现象.脉冲形成后其属性只与SBS动态属性有关.