用表面态型半导体可饱和吸收镜实现Yb∶YAG激光器被动调Q锁模

制作了一种新型的半导体可饱和吸收镜——表面态型半导体可饱和吸收镜. 用表面态型半导体可饱和吸收镜作为被动锁模吸收体实现了半导体端面泵浦Yb∶YAG激光器被动调Q锁模. 在泵浦功率仅有1.4 W的情况下，获得了调Q锁模脉冲序列，锁模平均输出功率1 mW，锁模脉冲重复频率200 MHz     

半导体可饱和吸收镜被动锁模侧面抽运Nd:YAG激光器研究

利用半导体可饱和吸收镜(SESAM)锁模技术实现的超快脉冲激光器具有结构简单紧凑、脉冲序列稳定等优势,在许多领域有着重要用途,自问世以来受到国内外的广泛关注.分析了SESAM被动锁模侧面抽运固体激光器的具体要求,进行了不同条件下的SESAM被动锁模侧面抽运Nd:YAG激光器实验.获得了最高平均功率9.5 W,脉冲重复频率71 MHz,单脉冲能量约141 nJ的皮秒激光脉冲.对SESAM被动锁模侧面抽运Nd:YAG激光器进行了实验和理论分析,对实现高功率连续超短脉冲激光器进行了探讨.     

低阈值掺钛蓝宝石激光器实验研究

结合特殊的谐振腔设计和半导体可饱和吸收镜，建成了一台低阈值的自启动掺钛宝石激光器 . 分别用3％和12％的输出耦合镜，获得了阈值低至390mW和600mW的稳定锁模脉冲输出. 采 用12％输出耦合镜，在12W抽运时，输出平均功率为114mW，对应的典型脉宽为17fs，谱宽 为47nm. 相对于以往的低阈值克尔透镜锁模激光器，锁模工作的范围区域加宽，减小了操作 难度，提高了稳定性. 关键词： 低阈值 半导体可饱和吸收镜 克尔透镜锁模 掺钛蓝宝石激光器     

用于钛宝石激光器自启动锁模的半导体可饱和吸收镜

报道国内首次制作的宽带低损耗半导体可饱和吸收镜（SESAM）。该反射镜已经成功用于钛宝石飞秒脉冲激光器的自启动锁模运转。     

半导体可饱和吸收镜启动的高功率飞秒掺钛蓝宝石激光器

半导体可饱和吸收镜（SESAM）启动的高功率飞秒掺钛蓝宝石激光器,在Ar^ 激光器10W全线抽运下,其平均输出功率达到1.7W,脉冲宽度小于16fs,斜率效率为22％。文中对半导体可饱和吸收镜自启动的动力学过程进行了实验研究。这种自启动、高功率、窄脉宽的飞秒激光器将具广泛的应用前景。     

半导体可饱和吸收镜作为被动调Q吸收体的发展状况

简介了近年来发展起来的若干种新型固体激光器被动调Q用吸收体：掺Cr4+系列，Cr，Nd∶YAG自调Q激光晶体，人眼安全激光器被动调Q用吸收体，GaAs吸收体，半导体可饱和吸收镜。着重介绍了固体激光器和光纤激光器调Q用半导体可饱和吸收镜的原理、研制方法及应用状况。     

含负克尔效应半导体可饱和吸收镜的五镜腔飞秒钛宝石激光器的理论分析

基于半导体可饱和吸收镜(SESAM)的负克尔效应，对含SESAM的五镜腔进行了理论计算和分析.结果表明，由于SESAM的负克尔效应，与没有SESAM的相比，锁模激光器的稳区在上稳区的内边缘有明显扩展，这使得激光器锁模启动的工作点更加靠近直流运转时的稳区边缘，从而获得更大的非线性因子.这说明SESAM的可饱和吸收机理具有锁模自启动效应外，其负克尔效应也有助于锁模的自启动. 关键词： 半导体可饱和吸收镜 负克尔效应 五镜腔     

激光二极管侧面抽运Nd∶YAG锁模激光器的研究

利用谐振腔的稳定条件对激光二极管侧面抽运的 Nd∶YAG锁模直腔的稳区特性和谐振腔内的光斑分布进行了分析。根据对腔参量的分析,选取合适的腔参量设计了一个简单的侧面抽运直腔,该谐振腔腔形简单,没有像散,振荡光模式好,有利于激光器的锁模运转。实验中采用国内自行研制的半导体可饱和吸收镜,实现了激光二极管侧面抽运半导体可饱和吸收镜锁模Nd∶YAG激光器的连续锁模运转,平均输出功率为 2 W,锁模脉冲宽度为10 ps,重复频率为100 MHz。结合实验结果进一步讨论了半导体可饱和吸收镜的一些参量如饱和恢复时间、调制深度等对实现稳定连续锁模的影响。     

激光二极管侧面抽运Nd:YAG锁模激光器的研究

利用谐振腔的稳定条件对激光二极管侧面抽运的Nd：YAG锁模直腔的稳区特性和谐振腔内的光斑分布进行了分析。根据对腔参量的分析，选取合适的腔参量设计了一个简单的侧面抽运直腔，该谐振腔腔形简单，没有像散，振荡光模式好，有利于激光器的锁模运转。实验中采用国内自行研制的半导体可饱和吸收镜，实现了激光二极管侧面抽运半导体可饱和吸收镜锁模Nd：YAG激光器的连续锁模运转，平均输出功率为2W，锁模脉冲宽度为10ps，重复频率为100MHz。结合实验结果进一步讨论了半导体可饱和吸收镜的一些参量如饱和恢复时间、调制深度等对实现稳定连续锁模的影响。     

掺Yb3+双包层大模场面积光纤锁模激光器

报道了一种结构简单、运转稳定并可以输出高脉冲能量的被动锁模光纤激光器.激光器的增益介质为掺Yb3 双包层大模场面积光纤,具有非常低的非线性系数.利用非线性偏振旋转效应和半导体可饱和吸收镜结合实现自启动锁模,获得了平均功率为160 mW、重复频率为55.9 MHz(对应于3 nJ的单脉冲能量)、脉冲宽度为10.6 ps的激光脉冲输出.     

Optimization of the passively Q-switched laser with a novel central semiconductor saturable absorption mirror (C-SESAM)

The diode-pumped passively Q-switched laser, realized with a novel central semiconductor saturable absorption mirror (C-SESAM), can obtain much higher repetition rate and shorter pulse duration which have been proved theoretically and experimentally. Therefore, it is essential to optimize this kind of lasers to achieve many of the desired properties. The normalized rate equations are solved numerically, when the direct band-gap absorption of the InGaAs thin layer, the single-photon absorption (SPA) and two-photon absorption (TPA) processes of GaAs substrate are simultaneously considered. Some new normalized parameters are introduced and the key parameters of an optimally passively Q-switched laser are determined, including the optimal normalized coupling parameter and the optimal normalized saturable absorber parameters, which can maximize the output energy. A group of general curves are generated, and sample calculations for a diode-pumped Nd³⁺:YVO₄ laser with a novel central semiconductor saturable absorption mirror (C-SESAM) are presented to demonstrate the use of the curves and the relevant formulas.     

Yb3+:KY(WO4)2 laser with a fast saturable absorber

Quantum-well semiconductor structures with superlattice barriers and reduced recovery time of absorption are designed and manufactured. A saturable absorption mirror based on such a structure is used in the Yb³⁺:KY(WO₄)₂ laser. The mode locking at a repetition rate of 70 MHz yields an almost bandwidth-limited pulse with a duration of about 115 fs. The maximum mean power (1.57 W) is comparable with a CW power of 1.62 W, which indicates a relatively low level of nonsaturable loss in the saturable absorption mirror.     

Passively modelocked surface-emitting semiconductor lasers

This paper will review and discuss pico- and femtosecond pulse generation from passively modelocked vertical–external-cavity surface-emitting semiconductor lasers (VECSELs). We shall discuss the physical principles of ultrashort pulse generation in these lasers, considering in turn the role played by the semiconductor quantum well gain structure, and the saturable absorber. The paper will analyze the fundamental performance limits of these devices, and review the results that have been demonstrated to date. Different types of semiconductor saturable absorber mirror (SESAM) design, and their characteristic dynamics, are described in detail; exploring the ultimate goal of moving to a wafer integration approach, in which the SESAM is integrated into the VECSEL structure with tremendous gain in capability. In particular, the contrast between VECSELs and diode-pumped solid-state lasers and edge-emitting diode lasers will be discussed. Optically pumped VECSELs have led to an improvement by more than two orders of magnitude to date in the average output power achievable from a passively modelocked ultrafast semiconductor laser.     

Nonlinearly limited saturable-absorber mode locking of an erbium fiber laser

We describe an erbium fiber laser that is passively mode locked by a novel, precision antireflection-coated semiconductor saturable-absorber mirror that incorporates an additional two-photon absorber. It is shown that passive mode locking evolves from a Q-switching instability. The results are achieved by use of saturable absorbers that provide a large (15%) nonlinear (saturable) loss. Exploiting two-photon absorption can substantially reduce the peak power of the Q-switched pulses, which results in improved reliability of the laser. Moreover, two-photon absorption can be used to produce an optimal stability range for saturable-absorber mode locking.     

自启动被动锁模掺铒光纤激光器的研究

在非线性光纤环形镜非线性开关效应和块状半导体波导饱和吸收效应的共同作用下，实现了掺铒光纤激光器的自启动被动锁模，获得了十分稳定的锁模脉冲序列，观察到高次谐频锁模脉冲输出。分析了非线性光纤环形镜的非线性开关反射特性。     

中间镜式半导体可饱和吸收镜在Nd∶YVO4激光器中被动调Q特性研究

利用一种新型的中间镜式半导体可饱和吸收镜,成功实现了二极管泵浦Nd∶YVO4激光器调Q运转,获得的最短脉冲宽度为8.3 ns,最大平均输出功率为135 mW,重复频率在400 KHz到2 MHz之间.利用这种吸收体被动调Q得到的重复频率大大高于所知的大多数吸收体所进行的被动调Q的重复频率.     

Passive mode locking of a diode-end-pumped Nd:GdVO4 laser with a semiconductor saturable absorber mirror

We report an end-pumped and passive mode-locking all-solid-state laser. The laser consists of a Nd:GdVO4 crystal and a linear resonator with a semiconductor saturable absorber mirror that yield mode locking. We achieved stable continuous-wave mode locking with an 8-ps pulse duration at a 154-MHz repetition rate. The average output power was 600 mW with 4 W of pump power. To our knowledge this is the first report of the use of a Nd:GdVO4 crystal for mode locking with a semiconductor saturable absorber mirror.