固体谐波多波长拉曼激光器

研究了多谐波固体激光器在气体中的受激拉曼散射，获得了多波长激光输出。利用Nd：YAG激光的二倍频、三倍频及四倍频的激光输出在氢气和甲烷气体中的受激拉曼特性获得多个波长的拉曼输出，波长范围覆盖紫外到可见光甚至近红外。列出了常用的几种拉曼工作气体，其中氢气和甲烷各有优缺点，而两者的混合气体一方面弥补了氢气频移过大的缺点，另一方面抑制了甲烷的易分解性。利用缓冲气体和混合气体优化拉曼激光的输出。给出了24个拉曼波长的功率输出数据，其中功率较大的有13个波长。多谐波固体激光与受激拉曼散射结合的多波长拉曼激光器在激光雷达等领域有广泛的应用。     

高功率皮秒激光泵浦受激拉曼散射腔研究

为了获得高平均功率的皮秒宽谱段激光,同时 减小整个光学系统的体积,本文从理论和实验两方面研究了高功率皮秒激光泵浦受激拉曼 散射(SRS)振荡腔。 通过分析SRS过程中同时发生的物理过程,将高功率泵浦下的拉曼晶体内多种 非线性效应简化 为晶体在简单等效透镜下的SRS,并通过实验测量单通SRS光的发散角,计算得到了高 功率泵浦下的拉曼晶体等效透镜的曲率半径,在此基础上设计了稳定高效的SRS振荡腔,通 过对比实验验证了此拉曼振荡腔的高效性,实现了波段覆盖532～698nm、最高输出功率为1.32W的皮秒SRS同轴激光的输出。在相同波 段覆盖范围内,是已报道的最高平均输出功率。     

多波长泵浦宽带拉曼放大器功率增益研究

受激拉曼散射（SRS）的Stokes波谱线型比较复杂,本文分别用Gauss线型和Lorentz线型,研究多波长泵浦宽带Raman放大器的增益特性,提出宽带增益平坦的多波长泵浦方案,研究表明增益平坦程序与泵清波频率间隔密切相关。对G．652、G．653、G．655光纤和新型大有效面积非零色散平坦光纤的Raman放大增益分别进行了研究,结果表明Raman增益与光纤种类和光纤传输性有关,特别是随光纤有效纤芯面积的增大而明显减小。     

新型受激拉曼散射激活晶体光谱和固态受激拉曼散射激光器

拉曼散射发现后不久 ,在 G.Placzek建立的一般理论中 ,能找到拉曼散射受激过程的内涵。然而 ,光的受激拉曼散射直到激光辐射源出现以后才被发现。俄国科学家 N.G.Basov和 A.M.Prokhorov为激光的发明做出的贡献赢得了全世界的承认。 1 96 2年 ,E.J.Woodbury和 W.K.Ng用硝酸基苯克尔吸收池研究红宝石激光器 Q开关的时候 ,发现受激拉曼散射效应。在激光光谱中 ,他们观测到一个高强度的相对于激光频率频移1 34 5 cm- 1 的红外辐射成分 ,这种现象后来归结于受激拉曼散射效应。从那以后 ,这个令人着迷的非线性现象及其在激光光谱学和激光工…     

固体拉曼激光器

简要介绍了固体拉曼激光器的研究现状,总结了几种常用的固体拉曼晶体[LiIO3,Ba(NO3)2,CaWO4]的受激拉曼实验特性,并对如何设计各种形式的拉曼激光装置以取得良好的频率转换做了分析。最后对固体拉曼激光器的发展做了展望。     

低频移拉曼模式多阶级联的1.7 μm激光器

基于固体介质的拉曼频率变换是产生新波段激光的有效技术方案。利用1572 nm KTP光参量振荡器腔内泵浦KGW晶体,实现了1616 nm （2阶）、1638 nm （3阶）、1662 nm （4阶）、1686 nm （5阶）、1711 nm （6阶）拉曼激光输出,其中1711 nm占据主导地位。激光器最大总平均输出功率为1.13 W,最小脉冲宽度为20 ns。该多阶级联拉曼变频对应的单阶平均拉曼频移为86 cm?1,与文献报道的KGW晶体低频拉曼模式相吻合。采用1572 nm KTP光参量振荡器作为拉曼激光器的腔内泵浦源有两个优势,一方面可以有效拓展拉曼变频的输出波长,另一方面可以基于光参量振荡器的脉冲窄化特性为后续多阶拉曼转换提供高强度的泵浦光。通过引入多阶级联拉曼变频的方案,为有效利用固体介质非常规低频移拉曼模式提供了新思路。     

多泵浦拉曼放大器增益特性的仿真与分析

合理简化了多泵浦光纤拉曼放大器功率传输方程,利用多步平均功率法进行数值计算得到了密集波分复用系统信号的合成拉曼增益。借助该简化模型研究了多泵浦光源的个数、输入功率和波长分布对信号拉曼增益的影响,简单分析了实现超宽带平坦拉曼增益的多泵浦波配置原则,为多泵浦光纤拉曼放大器在密集波分复用系统中的应用提供了有价值的参考。     

基于拉曼晶体的多波长激光技术研究进展

利用受激拉曼散射效应,以拉曼晶体作为介质,可产生同轴输出的多波长激光信号,该种激光器具有结构紧凑、脉冲能量高和波长可调谐等特点,在全色激光成像与显示、光电对抗等领域有着重要的应用前景。本文介绍了受激拉曼散射基本原理和常用拉曼激光器结构,研究了国内外基于拉曼晶体的多波长激光技术的研究进展,总结了利用受激拉曼散射产生多波长激光存在的不足。针对目前受激拉曼散射高阶散射光较难生成,生成的多波长激光信号覆盖谱段较窄,输出功率较低,调谐方式单一等问题,提出了今后多波长激光技术发展方向。     

Preparation of multi-wavelength infrared laser diode

We prepare a new type of multi-wavelength infrared laser diode with four chips, three wavelengths （865 nm, 905 nm and 1064 nm） and two working modes （pulse and single）. The preparation technology of the diode includes two key processes： heat-sink and packaging processing technique to package four different chips on a same heat-sink. The experimental results show that four output peak-wavelengths of the prototype diode all possess favorable stability.     

光纤喇曼激光器及多波长输出的分析

为了优化设计光纤喇曼激光器的各项参数,采用喇曼激光器的基本理论模型模拟分析了用DCF光纤做增益介质的光纤喇曼激光器的输出特性,提供了激光器优化设计的方法;通过改变光纤的长度和输出端面的耦合效率得到最优的激光输出;以及改变泵浦功率时输出激光功率的变化情况;并进一步分析了多波长的光纤激光器,得到四波长输出的光纤激光器。     

激光器免温控泵浦源的多波长选择理论

为了实现激光器在一定温度范围内LD泵浦源免温控稳定工作,具有较高并且稳定的泵浦光吸收效率,分析了DPL激光器中LD发射谱和Nd:YAG增益介质吸收谱的特点及匹配问题,据此提出了一种激光器免温控泵浦源的多波长选择理论和方法,同时增加泵浦光吸收长度克服Nd:YAG吸收谱和LD波长失配的不利影响。优化设计了一个波长为802.35 nm@25℃、813.15 nm@25℃和810.95 nm@25℃的三波长LD泵浦方案,计算结果表明:在一定吸收长度下,多波长泵浦光吸收效率可达73.96%,并且在-15.7~65.7℃宽温度波动范围内,激光器输出能量不稳定度优于5%。同时还模拟分析了增益介质吸收长度和掺杂浓度对泵浦光吸收效率的影响。     

Study on picosecond pulse-train multi-wavelength Raman laser operating at two Raman modes without tuning

The Stokes line of multi-mode Raman laser was limited by low conversion efficiency of higher-order Stokes and the competition between pure cascaded stimulated Raman scattering(SRS) and Four-wave-mixing(FWM) process which will deplete the pump of SRS process. Through developed pulse-train synchronously pumping technique and two-Raman-mode operating, the orders of output Stokes was improved. With average power of 220 mW, the developed a Raman laser providing up to 5 orders Stokes output, containing up to 16 laser lines without tuning operating and four-wave-mixing process.     

Picosecond laser pulses

The broad bandwidth and long storage lifetimes of Nd³⁺: glass and ruby lasers have made possible the generation of picosecond laser pulses having peak powers it excess of one gigawatt and repetition rates in the microwave range. The numerous application areas of these pulses include research in nonlinear optics, transient response of atomic and molecular systems, optically generated plasmas, spectroscopy, ranging, optical information processing, and high-speed photography. This paper reviews several experimental techniques for generating, measuring, and utilizing these ultrashort laser pulses.     

Using an injection-locked diode laser to pump a CW Raman laser

We demonstrate the use of an injection-locked diode laser (792 nm) as the pump source for a continuous-wave (CW) Raman laser with Stokes emission at 1182 nm. Phase modulation of the master signal is imparted to the slave laser output in order to generate an error signal for phase/frequency locking via the Pound-Drever-Hall method. To illustrate the utility of this technique, we achieve the highest pump rate yet observed for a CW Raman laser (>90 times threshold) and compare the data to the existing theory. We also show how current modulation of the slave laser can eliminate the need for an electrooptic modulator in the system altogether     

Raman beam cleanup of a severely aberrated pump laser

Distortion-free amplification of a diffraction-limited (D.L.) Stokes beam in a hydrogen Raman amplifier pumped by a severely aberrated XeCl laser (120 × D.L.) has been observed with an attendant power conversion efficiency of the order of 30 percent. The corresponding increase in available far field intensity over that from the aberrated pump beam is 5000. An optical integrator was used to focus the poor quality pump beam into the amplifier and to remove all near-axial components in the pump field. Numerical study of this process using a two-dimensional propagation code shows that the presence of near-axial pump components can cause phase matched four-wave mixing interactions with the Stokes, leading to increased angular divergence of the amplified Stokes beam and the development of secondary sidebands in the far field. When a moderately aberrated pump beam (20 × D.L.) was used, spatial sidebands of the Stokes beam were generated due to increased coherence length for the mixing process, significantly reducing the far field Stokes intensity.     

Time-division multiplexed Raman pump experiment using a tunableC-band laser

In this letter, we report on the first experimental demonstration of a time-division multiplexed frequency-swept Raman pump used to adaptively flatten the gain of a Raman amplifier. By means of a single, but tunable Raman pump laser operating in the C-band, an ON-OFF Raman gain flatness of 0.6 dB over 15 nm (or 1.5 dB over 30 nm) at an average ON-OFF Raman gain of 22 dB could be achieved for a pump wavelength range of 22 nm     

The dependence of Raman gain on pump laser bandwidth

The dependence of Raman gain upon laser bandwidth is analyzed in terms of a set of coupled mode equations. The analysis predicts that the Raman gain is independent of pump laser bandwidth within limitations set by dispersion in the Raman medium. These results are verified for rotational and vibrational transitions in H2using a variable bandwidth Nd:YAG laser.