Ar~ 激光器的被动锁模

一、前言关于Ar~ 激光器的被动锁摸技术最近已有报道。在这类系统中,为了被动锁定Ar~ 的模式,将若丹明6G(一种通常用作Ar~ 泵浦染料激光系统中增益介质的染料)放入Ar~ 激光共振腔内作为饱和吸收体。锁模Ar~ 脉冲依次对若丹明6G激光器进行内腔泵浦,以同步产生短的染料激光脉冲。但是,对于锁模染料激光脉冲没有任何全面的报道,也没有得出染料激光脉冲的详细特性。某些研究工作者对Ar~ 激光脉冲的特性作过更加广泛的描述,包括按碰撞脉冲锁模     

被动锁模染料激光器光脉冲成形研究

本文考虑了被动锁模染料激光器光脉冲成形机理:饱和增益、饱和吸收、群速弥散(GVD)、自相位调制(SPM)以及光谱滤波和线性损耗等因素,建立计算机模型,模拟光脉冲在腔内的形成,得到与实验一致的结果。     

主动锁模光纤激光器的孤子理论分析

系统考虑了光纤激光器腔构参数与锁模脉冲参数的制约关系,建立了完整形式的振幅调制主动锁模光纤激光器的稳态方程;据此方程分析了主动锁模光纤激光器腔参数对锁模孤子脉冲参数的影响;分析了无啁啾孤子脉冲形成条件。     

非线性偏振旋转锁模自相似脉冲光纤激光器的研究

利用耦合非线性薛定谔方程（CNLSE）为非线性偏振旋转（NPE）锁模自相似光纤激光器建立了一种新的数值模型.模型中,用CNLSE描述脉冲在单模光纤中的传播,在增益光纤中同时考虑了增益带宽和增益饱和作用,用传输矩阵描述构成NPE锁模的光学元件.优化了腔内净色散和光纤长度等参数,模拟了脉冲在激光腔内的演化特性,得到了典型的自相似脉冲运行区域及特点.在最佳自相似脉冲运行区域内,得到了能量约为7 nJ、脉宽约11 ps、线性啁啾的抛物脉冲.比较了不同腔内净色散条件下输出脉冲的特点,给出了三阶色散对输出脉冲的影响. 关键词： 自相似脉冲 非线性偏振旋转锁模 耦合非线性薛定谔方程 数值模拟     

正色散激光器中的增益导引孤子

采用非线性薛定谔方程模拟了全正色散介质激光器中实现脉冲锁模输出的动态过程,理论表明,不同于工作于净色散为负的孤子锁模激光器以及腔内具有色散延迟线净色散为正的色散管理孤子和自相似脉冲锁模激光器,在纯正色散介质构成的锁模激光器中,增益饱和和增益窄化对形成稳定的锁模脉冲起重要的作用,在两者的作用下脉冲形成增益导引孤子.采用不同的锁模方式在纯正色散光纤锁模激光器中得到了稳定的增益导引孤子锁模,实验结果与理论模拟一致. 关键词： 锁模 正色散 增益导引孤子     

对撞脉冲锁模Nd:TAG激光器的研究

本文报道了对撞脉冲锁模Nd:YAG激光器的腔型,在500MHz示波器上观察到了稳定的锁模脉冲串,测得平均脉宽为10ps左右;详细研究了染料浓度与锁模阈值的关系,并证实了泵浦能量增大时锁模多脉冲的出现。     

YAG激光同步泵浦染料激光器产生38fs光脉冲

研究表明,不用碰撞脉冲锁模技术,而由一台简单的线型腔染料激光器,就可成功地产生短达38飞秒的光脉冲。这种激光器用六镜折叠腔,其中有Rh6G和DOPCI两个喷流和一个棱镜对色散补偿器,用连续锁模Nd:YAG激光器的倍频输出同步泵浦。染料激光脉冲的平均功率为20mW,脉冲重复频率近100MHz。     

氩离子激光器同步泵浦染料激光器

研究了氩离子激光器的声光锁模参数.对4880(?)和5145(?)均获得了较稳定的锁模运转.锁模平均功率～300mW,脉冲宽度～200ps,脉冲强度起伏小于5%.用这台氩激光器同步泵浦一台折迭式象散补偿腔染料激光器,实现了同步锁模输出.在5840(?)处,其脉冲宽度小于10ps,平均功率～20mW.波长调谐范围是5700～6200(?),并着重研究了腔长或频率失调对锁模的影响.     

非腔长匹配相干叠加脉冲锁模激光器的理论研究

提出了一个新的非腔长匹配相干叠加脉冲锁模激光器的物理模型,建立了它的数学方程,并进行了模拟计算.计算结果给出了各个参数对相干叠加脉冲锁模激光器运转的影响,以及脉冲宽度压缩速度和各参数之间的关系,获得了实现非腔长匹配相干叠加脉冲锁模激光器运转的最佳条件.     

对撞锁模染料激光器中锁模脉冲列的耦合效应

论述了在对撞锁模染料激光器中必然存在锁模脉冲列耦合效应,此效应使输出脉冲较宽,且脉宽不稳定。用适当加厚锁模染料层等办法减弱该效应会使脉冲变窄且脉宽稳定。     

20 ps pulse generation by an excimer laser pumped double self-Q-switched distributed feedback dye laser

The behaviour of an excimer-laser-pumped distributed feedback dye laser (ELP DFDL) using a mixture of saturable absorber and laser dye as an active medium was studied. In a DFDL self-Q-switching occurs because of the population inversion dependence of the feedback. If the DFDL contains absorber saturation of the absorption by the leading edge of the created laser pulse also causes Q-switching. As a result of this double self-Q-switching, mixing a saturable absorber into the laser dye, the laser pulses become shorter and more stable. This was demonstrated experimentally. Mixing Rhodamine B into the dye solution of a Coumarin 153 ELP DFDL, a six-fold reduction in the pulse duration and a more than two-fold reduction in the pulse energy instability were observed. The experimental results were in good qualitative agreement with the predictions of a simple rate equation model.     

Theory of passively mode-locked cw dye lasers

The circulation of an ultrashort light pulse in a continuously pumped modelocked dye laser with a linear cavity configuration containing the active dye, the saturable absorber and a bandwidth-limiting elements is treated. The steady-state condition that the pulse shape reproduces after each cavity round-trip leads to a nonlinear integro-differential equation for this pulse shape. An approximate method for the solution of this equation not limited to the case of low laser gain and small pulse energies is given. The stable single pulse region and characteristic pulse parameters, as energy, duration, intensity and asymmetry, are considered in dependence on the laser parameters.     

High power subpicosecond pulse generation from a synchronously pumped dye laser combined with an external compressor

A new scheme of subpicosecond pulse generation based on a dye laser is described. Output pulses of 15 ps from a rhodamine-6G laser pumped synchronously by a frequency-double mode-locked Nd: YAG laser are compressed into 0.8 ps pulses of 2 MW by two passes of saturable absorber (DODCI) and saturable amplifier (rhodamine-6G). The technique is useful for generating widely tunable, high power repetitive subpicosecond pulses.     

Undamped relaxation oscillations due to self-gain-switching of laser dye mixtures

Undamped relaxation oscillations were observed from a short, simple dye laser using a laser dye mixture which was pumped at 337 nm using ns pulses. The dye solution contained Rh101 as first laser dye, together with DTDCI in double function as saturable absorber and second laser dye. Two trains of intense laser pulses were generated near 619 and 685 nm, with pulse durations of ca. 4 and 2 times the resonator transit time, respectively. This method of short-pulse generation is related to double mode-locking of dye lasers. Model calculations are used to describe the pulse generation by self-gain-switching, and to estimate radiative and nonradiative contributions towards saturation of the absorber dye.     

Temporal dynamics of high repetition rate pulsed single longitudinal mode dye laser

Theoretical and experimental studies of temporal dynamics of grazing incidence grating (GIG) cavity, single-mode dye laser pumped by high repetition rate copper vapour laser (CVL) are presented. Spectral chirp of the dye laser as they evolve in the cavity due to transient phase dynamics of the amplifier gain medium is studied. Effect of grating efficiency, focal spot size, pump power and other cavity parameters on the temporal behaviour of narrow band dye laser such as build-up time, pulse shape and pulse width is studied using the four level dye laser rate equation and photon evolution equation. These results are compared with experimental observations of GIG single-mode dye laser cavity. The effect of pulse stretching of CVL pump pulse on the temporal dynamics of the dye laser is studied.     

The effect of saturable absorber lifetime in picosecond pulse generation. II. The cresyl-violet laser

Picosecond pulse generation in a pulsed cresyl-violet laser, mode-locked by four saturable absorbers (DTDCI, DDCI, DCI, and DCI'), of different relaxation times, has been directly studied. In contrast to the ruby laser case, the ultimate pulse duration is largely independent of the absorber lifetime. Pulses of ? 4 psec duration are obtained from a cw Rhodamine B dye laser mode-locked with cresyl-violet.     

Theory of passive mode-locking of CW dye lasers with contacted and non-contacted absorbers

A theoretical treatment of the influence of a saturable absorber in close contact with a highly reflecting mirror on a light pulse is given. The shaping of a Gaussian pulse during a single passage through such an absorber is calculated for various absorber lengths. The influence of absorber position and length on the pulse parameters and the stability of a continuously pumped dye laser are investigated. The shortest pulses and the most favourable operation conditions of the laser are to be expected in the case of a short contacted saturable absorber.     

Chirped and chirp-free femtosecond pulses in passively mode-locked dye lasers

Femtosecond light pulse generation in a ring laser and its propagation properties are described. The basic principles and some theoretical aspects of the pulse generation process in dye lasers are summarized taking into account the influence of the amplifier, of the saturable absorber, of the glass path and of mirrors. Phase modulation arising from multilayer dielectric mirrors has been calculated and measured by determination of an equivalent intracavity glass path length. The main source of phase modulation (chirp) seems to be the saturable absorber.     

Two-wavelength operation of a femtosecond ring dye laser

We report on two-wavelength operation of a CPM ring dye laser employing Rhodamine 6G as gain medium and a new styryl dye as saturable absorber. Two trains of femtosecond pulses at different wavelengths are simultaneously generated under proper alignment of the laser. The secondary pulse train is attributed to the laser action of the absorber dye. Auto- and cross-correlation measurements are performed to determine the temporal characteristics of the laser in the double mode-locking regime.