用钛宝石再生放大器产生高重复率啁啾脉冲列

针对啁啾脉冲放大技术建成的钛宝石激光装置，提出一种获得高重复率激光脉冲列的方法.通过改变钛宝石再生放大器中泡克耳斯盒电光开关的传统工作模式，使得腔内放大的脉冲从某特定时刻起，每当在腔内往返一次就以一定的倒出比例（倒出率）倒出腔内脉冲能量的一部分，从而可以在有限的时间段内产生高重复率的啁啾激光脉冲列.基于Franz-Nodvik放大理论，建立了该高重复率再生放大器的理论模型，通过数值计算，系统地分析了初始增益、倒出时刻、倒出率对输出的脉冲序列的影响.在抽运功率为35mJ、倒出率为1/2的实验条件下，通过腔外的脉冲数量选择器，在一个抽运周期内的有限时间段内已获得了14个幅度相近、单脉冲能量约为0.02mJ、重复率为100MHz的啁啾脉冲序列.从此啁啾脉冲列中选取数个脉冲，通过10TW级的激光系统放大和压缩，已获得100MHz重复率的飞秒太瓦级脉冲列. 关键词： 高重复率 多通放大 啁啾脉冲放大 钛宝石激光器     

电光腔倒空与调Q射频波导CO2激光器

报道电光腔倒空与调Q射频波导CO2激光器,获得了电光腔倒空与调Q脉肿激光输出,并用调节电光晶体电压的方法控制腔倒空与调Q脉冲激光峰值功率;调节晶体电压脉冲宽度,可控制腔倒空与调Q激光的脉冲间隔,达到编程输出的目的。理论上分析了电光腔倒空过程。     

二极管泵浦Nd:YAG激光器的脉冲间隔调制

在激光通信线路可,腔倒空Nd:YAG激光器用于产生光脉冲,用脉冲间隔调制来对数据进行编码。三组GaAs二极管连续泵浦一个端面镀有高内反射膜的Nd:YAG棒。偏振光分束器以90°角反射s偏振光,形成L形状的激光腔。根据偏振相对于所加电压的延迟,铌酸锂调制器调制传播功率。产生     

声光调制器在激光腔倒空技术中的应用

本文介绍了以36°Y切铌酸锂为换能器,以熔石英为声光互作用介质,驱动频率为389。5MHz的声光调制器的设计;计算并选定了换能器的各镀层厚度,研制成了用于激光腔内的中心频率389.5MHz声光脉冲调制器;叙述了该器件在同步泵浦染料激光器腔倒空技术中的应用。实验表明,当驱动平均功率约0.2W时,用该器件所实现的激光腔倒空的倒空比约40％。     

基于频移反馈腔的全光纤射频调制脉冲激光研究

射频调制的脉冲激光是激光雷达探测领域内的一项重要研究内容.根据声光斩波器的强度和频率调制特性,设计了基于频移反馈腔的全光纤射频调制脉冲激光.理论上,建立了基于频移反馈腔的激光外差相干理论模型,并进行了数值仿真.根据理论模型,实验上严格控制频移反馈腔的长度和声光斩波器触发信号的周期,在100 MHz的射频信号驱动下,产生了脉冲宽度110 ns、重复频率约20 kHz的具有最高700 MHz射频调制的脉冲激光(脉内调制激光);同时微调斩波周期可以实现脉冲前沿或后沿的多样性射频调制.通过改变反馈腔内光纤放大器的输出功率实现了射频调制深度的连续可调,最高达到了0.67.     

4.5MW小型化全固态腔倒空飞秒掺钛蓝宝石激光器

研制了国内首台腔倒空克尔透镜自锁模掺钛蓝宝石激光器,该激光采用二极管抽运的全固态连续波532nm激光抽运.在5.4W的抽运功率下,获得了峰值功率大于4.5MW、脉宽小于18fs的稳定锁模脉冲,其重复频率可低至20kHz,所占尺寸约53.5cm×20.5cm.据知,此结果是迄今重复率最低、结构最紧凑的声光腔倒空飞秒激光器件 关键词： 掺钛蓝宝石 腔倒空 飞秒脉冲 克尔透镜锁模     

具有脉冲增益调制自由电子激光器的光场混沌

用唯象理论模型讨论了储存环型自由电子激光振荡器的光场混沌问题.通过理论分析和数值模拟发现:当激光共振腔内的增益调制由周期振荡型变为周期脉冲型时,随着调制参数的改变,光场强度随时间的变化仍然要经过一个由倍周期分叉进入混沌状态的过程。相应的最大Lyapunov特征指数证明了光场混沌的存在。进一步研究表明:周期脉冲型增益调制比周期振荡型增益调制更接近于实际情况,因为它给出的光场时间结构与实验测得的结果更接近.     

电光腔倒空激光二极管抽运Nd∶YAG锁模激光器

设计了一个简单的直腔,将电光腔倒空与激光二极管端面抽运Nd∶YAG半导体可饱和吸收镜锁模激光器结合,实现了锁模脉冲的产生、放大和输出。在连续抽运功率5 W的条件下,获得了脉冲宽度为11 ps的锁模单脉冲输出和脉冲宽度为200 ns的调Q脉冲输出,腔倒空单脉冲能量为30 nJ,重复频率为10 Hz。连续锁模运转时单个锁模脉冲的能量约为2 nJ,利用腔倒空将单脉冲的能量提高了15 倍左右。文章详细讨论了腔倒空脉冲及调Q脉冲的产生机理,并分析了加在电光晶体上的高压电脉冲以及偏振片的偏振度对腔倒空脉冲及调Q脉冲的影响。     

电光腔倒空激光二极管抽运Nd:YAG锁模激光器

设计了一个简单的直腔。将电光腔倒空与激光二极管端面抽运Nd：YAG半导体可饱和吸收镜锁模激光器结合，实现了锁模脉冲的产生、放大和输出。在连续抽运功率5W的条件下。获得了脉冲宽度为11ps的锁模单脉冲输出和脉冲宽度为200ns的调Q脉冲输出，腔倒空单脉冲能量为30nJ，重复频率为10Hz。连续锁模运转时单个锁模脉冲的能量约为2nJ。利用腔倒空将单脉冲的能量提高了15倍左右。文章详细讨论了腔倒空脉冲及调Q脉冲的产生机理，并分析了加在电光晶体上的高压电脉冲以及偏振片的偏振度对腔倒空脉冲及调Q脉冲的影响。     

100 kHz腔倒空薄片激光器理论与实验研究

对100 kHz运转的腔倒空薄片激光器的输出特性进行了理论和实验研究。首先建立起腔倒空薄片激光器的速率方程理论模型，模型中考虑了单位时间谐振腔中新增的自发辐射光子数，对其占总自发辐射光子数的比例进行了分析，并结合一些参数进行了仿真。进一步搭建了重复频率为100 kHz的腔倒空薄片激光器实验装置，获得了平均功率为253 W的纳秒激光脉冲输出，光光效率约为35.2%,脉冲宽度为10.4 ns,单脉冲能量为2.53 mJ,脉冲的峰值功率超过了200 kW,x和y方向的光束质量M²分别为9.77和9.27。针对腔倒空调Q的动力学稳定性问题，研究了普克尔盒开关时间对输出平均功率和输出脉冲稳定性的影响，实验中观察到了倍周期分岔和确定性混沌现象，从理论上对这个现象进行了仿真分析，仿真结果可与实验结果相符。     

Near-infrared cavity-dumped femtosecond optical parametric oscillator

We demonstrate a high-energy near-infrared cavity-dumped femtosecond optical parametric oscillator (OPO) based on periodically poled lithium niobate. The laser generates 90 nJ pulses at a repetition rate of up to 1 MHz when synchronously pumped by 800 mW output from a femtosecond Ti:sapphire laser. The laser is broadly tunable from 1.0 to 1.5 microm in the signal branch, with a pulse duration of < 60 fs at 1.2 microm. High intracavity power is achieved by running the laser in the regime of positive group-velocity dispersion.     

用腔倒空Nd：YAG激光器对fs超短脉冲的同步放大

实现了用腔倒空Nd:YGA激光器对fs超短脉冲放大器的同步泵浦。由碰撞锁模环形染料激光器产生的80fs脉冲经二级染料放大后,实现放大倍数6.2×10~4,输出超短脉冲峰值功率～2×10~7W。     

Near-infrared optical parametric amplifier at 1 MHz directly pumped by a femtosecond oscillator

We demonstrate a high-average-power optical parametric amplifier directly pumped by a cavity-dumped Yb:KYW mode-locked laser oscillator at 1 MHz repetition rate. The two-stage system uses periodically poled lithium niobate crystals both for optical parametric generation and for power amplification. We obtain average powers as high as 190 mW with 220 fs average pulse widths and wavelength tunability in the 1.3-1.6 microm (signal) and 3.1-4.6 microm (idler) range.     

Ultrahigh-resolution coherence spectroscopy by means of periodic excitation with picosecond pulses

The feasibility of ultrahigh-resolution coherence spectroscopy with a train of picosecond light pulses from a synchronously pumped mode-locked and cavity-dumped dye laser is demonstrated. Narrow resonances of periodic pulse excitation are observed whenever the pulse repetition rate of the laser of a higher harmonic coincides with the frequency splitting of coherently excited levels. The zero-field hyperfine splitting of the Na-ground state (1771.6 MHz) could be measured in the 2100th order of the excitation rate with a resonance halfwidth of 800 Hz.     

30-fs, cavity-dumped optical parametric oscillator

We demonstrate cavity dumping of a synchronously pumped optical parametric oscillator (OPO). The OPO delivers 30-fs pulses with energies as high as 13 nJ at up to 400-kHz repetition rates. The OPO's tunability ranges from 570 to 600 nm and is limited by the resonator mirror coatings. The time jitter between pulses of a Ti:sapphire laser and the cavity-dumped OPO pulses is smaller than 30 fs, permitting multicolor time-resolved spectroscopic experiments.     

Pulse properties of a synchronously mode-locked,cavity dumped,picosecond dye laser system

A synchronously mode-locked, cavity-dumped picosecond dye laser is described. The structure and intensity of the picosecond pulses measured under different conditions are reported. It was found that the structure of the pulses from the synchronously pumped dye laser depends critically on the length of the Ar⁺ laser pulses. At the shortest Ar⁺ laser pulses of about 70 ps the dye pulses are as short as 1.1 ps. With Ar⁺ laser pulses of 200 ps the dye laser pulses contains a broad satellite pulse which contains a large fraction of the total intensity. When a cavity dumper is added to the system one gets dye laser pulses 15–20 ps long with a substructure, which indicates incomplete mode-locking. Well mode-locked 1.5–2.0 ps pulses were obtained in the red part of the dye laser action spectrum, i.e. 620–650 nm for R6G, 595–608 nm for R 110 and 657–662 nm for RB, respectively. Addition of mode-locking dyes also improved the pulse quality at some wavelengths.     

Cavity-dumped mode-locked Nd:GdVO<Subscript>4</Subscript> laser at low repetition rate

We report a cavity-dumped mode-locked Nd:GdVO₄ laser with semiconductor saturable absorber mirrors at low repetition rate. In this laser system, a single mode-locked laser pulse is generated, amplified and cavity-dumped by means of electro-optic modulator at 1 to 10 Hz repetition rate. The energy of the pulse is about 150 nJ and the pulse duration is determined to be 10 ps.     

基于有源Fabry-Perot腔的激光脉冲延时自外差研究

对注入有源Fabry-Perot腔内的单纵模脉冲进行了延时理论分析, 计算了Fabry-Perot腔内增益, 并对脉冲输出进行了数值模拟, 结果表明当脉冲能量衰减到一定值时, 新增抽运粒子数提供的增益可以补偿腔内损耗, 延时脉冲的输出可以达到稳态. 然后利用激光二极管侧面抽运Nd: YAG激光器做为Fabry-Perot腔, 对外部入射的单纵模脉冲光进行了延时, 得到了延时时间2 μups、脉冲数量140个的实验结果. 最后利用有源Fabry-Perot腔对参考光进行延时, 声光移频器对信号光产生频移, 进行了外差实验, 实验结果与移频器的设置值相符, 误差在4%以内.     

12-fs pulses from a continuous-wave-pumped 200-nJ Ti:sapphire amplifier at a variable repetition rate as high as 4 MHz

We demonstrate a novel compact femtosecond Ti:sapphire laser system operating at repetition rates from 10 kHz to 4 MHz. The scheme is based on the combination of a broadband cavity-dumped oscillator and a double-pass Ti:sapphire amplifier pumped by a low-noise cw solid-state laser. Amplified pulses with an extremely smooth spectrum, a duration of only 12 fs, and less than 0.25% rms fluctuation are generated in a beam with M2 < 1.2. A maximum pulse energy of 210 nJ and an average output power of as much as 720 mW are achieved. This output energy is sufficient to generate a stable continuum in a sapphire disk.