Frequency and amplitude characteristics of a high repetition rate hybrid TEA-CO2laser

The envelope and frequency characteristics of the output pulse of a high repetition rate hybrid TEA-CO2laser are presented. Both the intrapulse and interpulse laser frequency stabilities are experimentally determined at repetition rates up to 300 Hz. The recovery of the CW laser signal following the generation of the TEA laser pulse is analyzed theoretically and experimentally. Short term reproducibilities of ±2 MHz are observed at a pulse repetition rate of 300 Hz with initial chirp rates of about 1.5 MHz/μs. Improvements and limits on power and repetition rate are discussed.     

Preionizer-induced pulsed-mode operation of a transverse-flowtransversely excited CW CO2 laser

A pulse-preionized, dc-excited, transverse-flow, CW CO₂ laser has been operated in pulsed mode without using a discharge power-switching scheme. The pulsation in laser power is produced by a pulsed current that flows from the dc power supply due to the collapse in the discharge impedance whenever a preionizer pulse appears. By properly choosing the preionizer-pulse repetition frequency, dc power-supply filter-capacitor value, and gas composition, the laser pulsation has been enhanced. This laser has been operated at 1-kW average laser power level in pulsed mode at 1.3-kHz pulse repetition frequency with a peak-to-average power ratio of 3.35 and laser-power modulation depth of almost 100%     

Mn/MnCl_2蒸气激光器

研制了以氯化锰为工作物质、氖作缓冲气体的连续脉冲锰蒸气激光器。观察到7根绿色激光谱线,激光输出的90％以上集中在5341谱线上。在重复率18.2千周时最大平均功率444毫瓦,效率0.05％。还观察到12900的红外激光输出。     

受激布里渊散射主被动混合调Q光纤激光器

基于瑞利散射和受激布里渊散射(RS-SBS)的被动调Q掺铒光纤(EDF)激光器的输出脉冲序列具有重复频率低、脉宽窄、功率高的特点,适合光时域反射(OTDR)系统对脉冲光源的基本要求,但是输出的脉冲序列不够稳定。提出在被动调Q激光腔中插入声光调制器(AOM)构成主被动混合调Q激光器。实验结果证明,这种混合调Q的方法既保持了声光调制器主动调Q激光器输出脉冲序列重复频率低而且稳定的特点,又发挥了瑞利散射和受激布里渊散射被动调Q机制动态速度快、输出脉冲宽度窄的优势。在120~200 mW的抽运功率条件下,得到的脉冲序列重复频率从30 Hz~90 kHz连续可调,脉冲宽度最小可达20 ns,峰值功率最高可达200 W,脉冲重复频率稳定度优于5%,脉冲幅度起伏不大于10%。脉冲峰值功率和脉冲宽度受抽运功率的影响不大,但随着调制频率增加,脉冲峰值功率降低而脉冲宽度加宽。     

TEA CO2激光脉冲整形用等离子体开关技术的进展

TEA CO2激光脉冲整形技术是高功率、高重复率、捷变频的TEA CO2激光器研究和用TEA CO2激光产生倍频、高次谐波技术的必不可少的重要技术.等离子体开关是目前应用较广的一种简单可行的激光脉冲整形技术.综述了等离子开关技术的原理和技术的发展过程,并对其作了简要分析,展望了其广泛的应用前景.     

LD side-pumped intracavity frequency-doubled high Nd：YAG green laser based on acousto-optic Q-switch

A highly efficient and high power green laser generated by intracavity frequency doubling of a diode-sidepumped Q-switched Nd：YAG laser has been demonstrated. In the simple L-shaped cavity geometry,the maximum green output power of 28.5 W was obtained with a pulse width of 95 ns at a pulse repetition rate of 10 kHz by using a LBO crystal for frequency doubling,corresponding to a conversion efficiency of 11% from diode pump power to pulse green power. At a pulse repetition rate of 1 kHz,6.9 mJ of pulse energy,25 ns of pulse duration and 276 kW of peak power were obtained.     

Generation of bandwidth-limited 2 ps pulses with 100 GHz repetition rate from multisegmented injection laser

A new dynamic regime in a multisegmented AlGaAs/GaAs DH injection laser has been realised. Generation of bandwidth-limited 100 GHz repetition rate pulses has been demonstrated. To our knowledge, this value is the largest ever reported for an ultrashort pulse repetition frequency obtained directly from a laser.<>     

Tunable Q-switched/cavity-dumped Z-fold CO/sub 2/ waveguide laser with two channels and common electrodes

A tunable Q-switched/cavity-dumped z-fold CO/sub 2/ waveguide laser with two channels and common electrodes is studied. The Q-switched and cavity-dumped pulse lasers have been obtained from the z-fold channel with the tunable pulse repetition frequency (PRF) of 1-70 kHz. At the Q-switched operation, the peak power is 730 W and the pulsewidth is 150 ns at the PRF of 10 KHz. At the cavity-dumped operation, the pulse laser width can be adjusted. The peak power is 6000 W with the pulsewidth of 20 ns and 3400 W for 32 ns. CW laser output has been obtained from the other channel and its frequency can be tuned by a piezoelectric transducer. The Q-switched and cavity-dumped pulse laser heterodyne waveforms are observed.     

MOPA方式高峰值功率脉冲光纤放大器模拟

为了研究如何从脉冲种子光经放大器后获得能量为毫焦级、纳秒级脉宽的激光脉冲,以及重频、受激喇曼效应对输出激光脉冲的影响,采用基于主振荡动率放大方式建立了3级脉冲双包层掺Yb光纤放大器的瞬态理论模型。在不同重频下对能量为10nJ、脉宽为100ns的脉冲种子光经放大后的脉冲能量、峰值功率、平均功率、脉宽及受激喇曼效应进行了数值模拟。计算数据表明,当重频小于200Hz时输出激光脉冲的能量、波形受重频的影响很小,可以忽略不计,在适当参量下受激喇曼效应对各级放大输出几乎没有影响。结果表明,适当选择3级光纤放大器的各项参量可以实现毫焦级的激光脉冲输出。     

Compact long-life high PRF 722.9 nm neutral lead vapor laser

Several new construction techniques for a compact long-life high pulse-repetition frequency (PRF) 722.9 nm neutral lead vapor laser are described. A quartz discharge envelope, coaxial oven, and controlled semiself-heating techniques were employed. An average laser output power of 90 mW at a pulse repetition rate of 5 kHz has been obtained with a discharge efficiency of 0.03 percent.     

Two contact, 1 cm long, monolithic extended cavity laser actively mode-locked at 4.4 GHz

A 1.0 cm long, two contact, monolithic extended-cavity laser has been fabricated and actively mode-locked at a repetition rate of 4.4 GHz to produce 9.0 ps optical pulses. Doubling of the optical pulse repetition rate of 8.8 GHz without changing the sinusoidal drive frequency is achieved by synchronously modulating two separate active regions.<>     

大能量长脉冲激光能量计吸收体温度特性

以大能量长脉冲激光能量的准确测量需求为牵引,针对激光能量计吸收体温度特性进行了数值分析研究。结果表明:吸收体内壁温度随脉冲结构呈周期性振荡,随着壁深的增加,震荡幅度迅速地降低,吸收体外壁温度周期性消失。单脉冲能量相同时,脉宽越短,吸收体内壁温升越高;重复频率越高,吸收体内壁温升越高。而总能量相同时,重复频率越高,内壁温升越低。通过对吸收体结构的优化设计,不仅能够获得序列长脉冲激光的总能量,而且可以获得低重频（一般不大于10 Hz）序列脉冲激光的每个脉冲能量,从而为长脉冲激光能量计的设计及应用等提供参考依据。     

A resistively stabilized XeCl laser operating at 200 Hz

We have explored the feasibility of stabilizing the discharge of a high repetition rate XeCl laser by providing distributed resistive ballasting of one of the transverse electrodes in the form of an array of resistive pins. This technique has enabled us to demonstrate operation of the laser at a (power supply limited) pulse repetition frequency of 200 Hz in a device which did not require forced circulation of the gas mixture.     

Gigabit optical pulse generation with FM mode-locked LiNdP4O12lasers

FM mode locking of an LiNdP4O12(LNP) laser with an intracavity modulator is reported. Mode-locked optical pulses with a pulse width of 49 ps at a repetition rate of 960 MHz, corresponding toc/2L(c:light velocity,L:cavity length), have been obtained. A pulse repetition rate as high as 2.88 GHz has been achieved with a multiple mode-locking technique.     

RF激励波导CO2激光器电光调Q实验研究

对用于激光主动成像雷达、运行于稳频选支模式的射频激励波导CO2激光器腔内插入CdTe电光晶体调Q实验进行了研究。计算了CdTe晶体的插入损耗并与实验结果取得了一致,对CdTe晶体和其配套的λ/4波片的热稳定性进行了研究,比较了加压式和退奢式电光调Q对激光脉冲特性的影响。激光调Q输出EH11模,重复频率41.67kHz,峰值功率达到360W,脉冲半宽度(FWHM)150ns。     

500 kHz波长锁定878.6 nm LD双端泵浦Nd:YVO4声光调Q激光器

报道了一种由波长锁定878.6 nm LD双端抽运Nd:YVO4声光调Q激光器,重复频率在500 kHz时具有稳定的1 064 nm脉冲激光输出。在重频为100 kHz,晶体吸收功率58 W时,获得18.2 W的1 064 nm激光输出,光-光转换效率为31.3%,脉宽为15.2 ns;在重频为500 kHz、晶体吸收功率58 W时,获得26.1 W的1 064 nm激光输出,光-光转换效率为45%,脉宽为44.2 ns,重频在100~500 kHz下具有稳定的脉冲输出,光束质量较传统模式下有明显提高,并且转换效率也有提升。实验表明:利用波长锁定878.6 nm激光二极管直接泵浦的方式,有利于降低晶体热效应、提高光束质量,提高光-光转换效率,获得窄脉宽的脉冲激光输出,并且在一定的温度变化范围内具有极好的温度稳定性。     

全光纤结构的脉冲光纤放大器

结合双包层掺镱光纤(YDCF)和主振荡功率放大(MOPA)技术,利用熔融拉锥的光纤侧面耦合器,设计和实验研究了全光纤结构的脉冲光纤放大器。在不同重复频率时,通过放大脉冲激光的输出光谱,对输出脉冲激光中的剩余抽运光和受激拉曼散射光功率进行了修正;并研究了激光脉冲的时域特性,以及在脉冲放大过程中对输出激光脉冲宽度的压缩作用。获得输出放大脉冲激光的主要参数:峰值波长为1075 nm,脉冲宽度为18~300 ns,重复频率为5~20 kHz,峰值功率达9.87 kW,斜率效率达52.2%,光束质量M2=2.0。同时,制作完成了一台结构紧凑、全光纤结构的脉冲光纤放大器样机,其最大外形尺寸为370 mm×270 mm×90 mm。     

Generation of ultrashort pulses from a neodymium glass laser system

A neodymium glass laser system capable of generating high-energy, ultrashort pulses at a convenient repetition rate is described. The effect of nonlinear frequency pulling on active mode locking is discussed. By minimizing the nonlinear frequency pulling, it is possible to routinely generate stable ~10-ps pulses at a 100-MHz repetition rate from the actively mode-locked oscillator. The regenerator amplifier increases the oscillator pulse energy to over 30 μJ at a 370-Hz repetition rate. Using intracavity self-phase modulation, the regenerative amplifier also broadens the pulse bandwidth to ~35 Å. By subsequent pulse compression while maintaining high energy, it is possible to produce 0.55-ps pulses with >10 μJ. An optical fiber pulse compressor further shortens the pulses to 30 fs (30 nJ), the shortest pulses ever generated at 1.054 μm from a neodymium laser system     

激光二极管抽运声光调Q高重复频率473nm激光器

实现了重复频率高达100kHz,紧凑的全固态激光二极管抽运的声光调Q473nm腔内倍频蓝光激光器。使用5mm长的Nd∶YAG作为激光介质,倍频采用了10mm长的I类非临界匹配LBO晶体,激光器外形尺寸为11cm×6cm×3cm。使用2W的激光二极管抽运,20kHz重复频率下,得到平均功率为64.8mW的473nm稳定输出,总光光转换效率为3.2%。在1kHz重复频率下,得到脉冲宽度为23ns,峰值功率接近700W,单脉冲能量达到16μJ的稳定的473nm激光脉冲。推导了准三能级系统的储能公式。此公式与以前的结果不同,认为有效储能时间不等于上能级寿命。通过实验结果的分析验证了这个结论。     

高重复率窄脉宽Nd:YVO4板条激光器

部分端面抽运的混合腔板条激光器是一种新型的全固态激光器,采用这种结构,实现了高重复率调Q运转.在脉冲抽运情况下,1 kHz运转时,得到脉宽4.6 ns,单脉冲能量4.5 mJ的激光输出.在连续抽运调Q输出情况下,5 kHz高重复率运转时,获得了脉宽6 ns,单脉冲能量3.1 mJ的脉冲序列输出,平均功率超过15 W;当重复率高达25 kHz时,得到脉宽9.5 ns,单脉冲能量1.2 mJ的激光输出,平均功率达30 W.实验结果表明,输出水平还有很大的提升空间.