光阴极注入器的驱动激光器

 光阴极注入器要求驱动激光器的激光时间抖动小、脉冲宽度窄、激光波长短和脉冲功率高。从原理和实验上介绍光阴极注入器的驱动激光器,包括连续波锁模振荡腔、时间同步,激光脉冲功率放大等;该激光器输出激光微脉冲宽度10ps,微脉冲时间抖动小于2ps,宏脉冲宽度2.5 μs, 峰值功率100kW, 已用于光阴极RF腔注入器实验,并获得了很好的结果。     

CFEL光阴极注入器驱动激光器的实验

在高功率自由电子激光初级实验装置（CFEL）研究中，驱动激光直接照射光阴极而发射电子，其性能将在很大程度上决定注入器乃至整个自由电子激光实验系统的性能：如电子束微脉冲宽度、电子束微脉冲流强、电子束微脉冲峰值抖动等。文中针对CFEL初期研究目标（3～8μm）对光阴极注入器的要求，对光阴极RF腔注入器的驱动激光器进行了方案设计，提出了驱动激光器的参数要求。根据方案进行了工程实施，购置了锁模激光器和时间同步器，放大与倍频系统正在研制当中。     

锁模激光脉冲串放大过程中的整形控制

 为了获得具有特殊要求的驱动激光,设计了一套以Nd:YVO4锁模激光器为种子光,用二极管激光器泵浦的Nd:YAG放大系统进行放大的激光系统。对放大过程中锁模激光脉冲串因增益饱和造成的脉冲串包络畸变以及对包络的整形控制进行了研究。实验获得能量为24 mJ的基频光,5.7 mJ的倍频光,0.608 mJ的紫外四倍频光;通过脉冲串整形控制,实现了包络顶部平整的紫外超短脉冲串输出,满足了光阴极注入器对驱动激光的特殊需求。     

7.13 W全固态1 319 nm宏微脉冲激光器

 研制了一台高效率全固态平均功率7.13 W的1 319 nm宏微脉冲激光器。激光器采用热稳Z形折叠腔,增益模块采用自行研制的准连续15个二极管芯片环形泵浦的Nd:YAG模块,采用主动声光锁模器作为锁模元件,并在腔内插入倍频KTP晶体对激光器的输出尖峰进行抑制。为了获得稳定的锁模状态,对激光器腔长进行了精确设计和调节。当激光器腔长与锁模器驱动频率匹配时,获取了宏脉冲重复频率400 Hz、脉宽约190 μs,微脉冲重复频率95.6 MHz、脉宽小于1.0 ns的1 319 nm激光脉冲。     

LiNbO3晶体压电应变光束调制器及激光锁模器解析

对轴切LiNbO₃晶体压电应变光束调制器(PESOM)及其作为激光锁模器的特性进行了详细解析。证明x切板共振器是作为激光锁模器的最佳运用方式,而y或z切板将不可避免地具有同时损耗调制和频率调制的双重作用,因而原则上不宜用于诸如激光锁模器这样的场合。     

2089 nm调Q锁模Tm,Ho∶CaYAlO4激光器

首次采用氧化石墨烯可饱和吸收体作为锁模启动元件在Tm,Ho∶CaYAlO4激光器中实现了稳定的被动调Q锁模运转。在3%输出耦合镜下,Tm,Ho∶CaYAlO4固体激光器获得了最低为293 mW的连续光出光阈值。在腔内引入氧化石墨烯可饱和吸收体后,当吸收抽运功率增大到1859 mW时,Tm,Ho∶CaYAlO4激光器进入稳定的调Q锁模运转状态。当抽运功率达到3 W时,获得中心波长为2089 nm、斜效率为10.1%、对应最大输出功率为213 mW的被动调Q锁模脉冲,重复频率为100 MHz,调Q包络中锁模脉冲的调制深度接近100%。     

LD泵浦、1W输出的Nd:GdVO4半导体可饱和吸收镜连续锁模激光器

报道了激光二极管泵浦、采用半导体可饱和吸收镜(SESAM)实现的Nd:GdVO4连续被动锁模运转激光器,得到了较大功率输出(接近1 W)的连续锁模激光.设计了四镜z型折叠激光谐振腔,在不同曲率半径的腔镜及不同的腔长条件下,分别获得了重复频率为250 MHz和100 MHz的稳定连续锁模脉冲输出.采用透过率1%的输出耦合镜,在泵浦功率为6.9 W时,得到连续锁模激光输出功率970 mW,光-光转换率达到13.7%.理论上讨论了调Q锁模的抑制措施,并结合实验结果进行了分析,得到了1063 nm稳定连续锁模激光输出,锁模脉冲光谱宽度1.2 nm(FWHM),用自相关仪测得脉宽为15.1 ps.     

注入锁定改善大口径稳定腔CuBr激光器的输出特性

报道了在稳定腔中采用注入锁定技术，钭自锁模ＣｕＢｒ激光脉冲成功地进行了注入锁定放大，得到了高平均功率的锁模铜激光脉冲，并且通过这种注入锁定，首次在稳定腔中得到了在２０ｍｍ光斑内空间高度相干的高功率铜激光辐射。     

光阴极RF腔注入器中激光脉冲的时间抖动

 介绍光阴极RF腔注入器中的驱动激光器,采用二极管泵浦的自锁模激光器,通过锁相,使输出激光脉冲的时间抖动小于2ps,实现激光脉冲同微波相位之间的严格同步,在实验上获得流强70A、能量2MeV、亮度4.4×10¹¹A/(m².rad²)的电子束。     

高功率CW锁模Nd:YAG激光器动力学特性研究

本文对具有热效应的锁模激光器的动力学特性进行了研究。采用内腔声光振幅调制器对CW Nd:YAG激光器进行锁模,在泵浦功率为3.5千瓦时,获得了平均功率达10W的锁模激光输出,其脉冲幅值稳定度优于4%。     

Analysis of a laser-diode end-pumped intracavity frequency-doubled passively Q-switched and mode-locked Nd:GdVO<Subscript>4</Subscript>/KTP laser with a semiconductor saturable absorber

A diode-pumped passively Q-switched mode-locked (QML) intracavity frequency-doubled Nd:GdVO₄/KTP green laser with a semiconductor saturable absorber is presented. Nearly 100% modulation depth for the mode-locked green pulses can be achieved at any pump power over 1.92 W. The width of the mode-locked green pulse was estimated to be about 150 ps. The mode-locked pulse interval within the Q-switched envelope of 320 ns and the repetition rate of 97.5 kHz were obtained, at an incident pump power of 4.4 W. The repetition rate of the mode-locked green pulses inside the Q-switched envelope was 140 MHz.     

被动谐波锁模掺Yb3+光纤环形激光器

 利用光纤的非线性偏振旋转效应产生可饱和吸收体的锁模机制，从掺Yb³⁺光纤环形激光器中得到稳定高阶谐波锁模光脉冲。理论分析了工作于正色散区的掺Yb³⁺光纤环形激光器的特性。实验中观测到了掺Yb³⁺光纤环形激光器3种不同演化方式产生高阶锁模光脉冲。4阶谐波锁模脉冲（107.2 MHz重复频率）经过1 m长高掺杂Yb³⁺光纤放大器放大后产生了平均功率100 mW，脉宽22.8 ps的脉冲，最后经过光栅压缩得到了平均输出功率20 mW，脉宽307 fs，脉冲中心波长1 051.2 nm，带宽13.76 nm的激光。     

高重复频率触发模式皮秒扫描相机

讨论了高重复频率扫描电路的研制,利用此扫描电路研制了扫描相机,使用掺钛兰宝石激光器进行了时间分辨率的标定,使用半导体激光器作为光源进行了脉冲宽度的测试.最高工作频率为：1 MHz,时间分辨率为：1.8 ps.     

高功率全光纤啁啾脉冲放大激光系统

采用基于非线性偏振旋转原理的光纤被动锁模激光器作为主振荡器。输出信号脉冲的重复频率为30MHz,脉冲半高全宽为265fs。信号脉冲通过全光纤啁啾脉冲激光放大系统展宽至100ps后,经过1级芯径10μm的光纤预放大器和1级芯径50μm的光纤功率放大器将脉冲平均功率放大至10W,斜率效率41.5%。输出脉冲经光栅压缩器将脉宽压缩至594fs。     

Harmonic Mode-Locked Ytterbium-Doped Fibre Ring Laser

We demonstrate a harmonic mode-locked ytterbium-doped fibre ring laser, which consists of a polarization-sensitive isolator, two polarization controllers, two 976nm laser diodes as the pump source and a two-segment ytterbium-doped fibre. Utilizing an additive pulse mode-locked technique based on nonlinear polarization evolution, the ytterbium-doped fibre laser can operate in mode-locked state by adjusting the position of polarization controllers. The cavity fundamental repetition rate is 23.78 MHz. We also observe the second- and third-harmonic mode locking in the normal dispersion region, and their repetition rates are 47.66 MHz and 71.56 MHz, respectively. Over-driving of the saturable absorber in the harmonic mode-locking pulse is analysed and discussed in detail.     

Tunable high energy giant chirped passively mode-locked Yb-doped fiber laser

A tunable, low-repetition rate, all-normal-dispersion Yb-doped fiber laser (YDFL) that is passively mode locked based on a phase shifted long period fiber grating (PS-LPFG) is demonstrated and proposed. The mode-locking mechanism of the laser is based on nonlinear polarization evolution (NPE). Using a PS-LPFG as the spectral filter in the laser cavity, the mode-locked output wavelength can be tuned continuously and smoothly over a spectral range of 10 nm, which is the first time implementation of a tunable giant chirped pulse with all-fiber format bandpass filter in YDFL. The maximum output pulse energy is 38.9 nJ at the repetition rate of 2.499 MHz.     

Bidirectional passively mode-locked soliton fiber laser with a four-port circulator

We present an all-fiber bidirectional passively mode-locked soliton laser with what we believe is a novel cavity configuration. Using a four-port circulator, we incorporate two different semiconductor saturable absorber mirrors (SESAMs) into the laser cavity, which enables bidirectional mode locking. The laser allows the generation of two independent countercirculating mode-locked pulse trains, each with an individual fundamental repetition rate that can be adjusted by varying the SESAM pigtail length. Two countercirculating pulse trains with repetition rates of 21.3 and 15.2 MHz are obtained simultaneously. By controlling the intracavity loss imposed on these two pulse trains, either one of the two pulse trains can be switched on or off. The bidirectional operation with other repetition rates is also demonstrated.     

Pulse picking by phase-coherent additive pulse generation in an external cavity

We have implemented a simple method for generating an "amplified" phase-coherent light pulse in which a pulse train of phase-coherent, equidistant input light pulses from a mode-locked Ti:sapphire laser is coupled into a ring cavity resonator whose length is matched to the mode-locked pulse repetition frequency at 82 MHz. Pulses are thus coherently superimposed and added inside the buildup cavity and form an intense pulse that is switched out from the cavity via a fast acousto-optic modulator. The method thus provides a pulse train at a reduced and controlled repetition frequency and with higher pulse energies than the original mode-locked pulses.     

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.     

High-energy dissipative soliton with MHz repetition rate from an all-fiber passively mode-locked laser

We experimentally demonstrate pulse energy enhancement in an all-fiber passively mode-locked laser operating in the large normal dispersion regime. By increasing the laser cavity length as well as its net cavity dispersion, the proposed laser, which is mode-locked by nonlinear polarization rotation, generates highly chirped dissipative solitons with pulse energies up to 9.4 nJ. The fundamental repetition rate is 2.3 MHz, and the pulse duration is 35 ps. Such low repetition rate as well as wide pulse width makes this mode-locked all-fiber laser a suitable oscillator to directly seed a fiber amplifier, which can be used as compact sources for high-power applications.