Properties of two-photon pumped cavity lasing in novel dye dopedsolid matrices

Two-photon pumped frequency upconversion cavity lasing at ~600 nm is accomplished in three types of dye-doped solid rods pumped with ~10 ns and 1.06-μm IR laser pulses. The dopant is a new dye, trans-4-[p-(N-ethyl-N-(hydroxyethyl)amino)styryl]-N-methylpyridinium tetraphenylborate, abbreviated as ASPT, which possesses a greater two-photon absorption cross section and stronger upconversion fluorescence emission than common commercial dyes (such as rhodamine). Three different materials were chosen as solid matrices: poly(2-hydroxyethyl methacrylate), VYCOR porous glass, and sol-gel glass. Using a Q-switched Nd:YAG pulse laser as the pump source, strong cavity lasing could be achieved in these three ASPT doped solid rods as well as in ASPT solution in a liquid cell. The spectral, temporal, and spatial characteristics of the cavity lasing output have been systematically investigated. The measured output-input characteristics, lasing lifetime, and damage threshold for the three different rods are presented     

Two- and three-photon absorption based optical limiting and stabilization using a liquid dye

It is experimentally shown that both two- and three-photon absorption in a high-molar-concentration chromophore system can be more efficiently utilized to accomplish optical power limiting and stabilization at laser wavelengths of 1.064 and /spl sim/1.3 /spl mu/m, respectively. The nonlinear absorbing medium is a novel liquid dye system, trans-4-[4-(dihexylamino)styryl]-N-(2-{2-[2-(2-hydroxy-ethoxy) -ethoxy]-ethoxy}ethyl)-pyridini um p-tosylate (abbreviated as ASEPT), consisting of chromophore molecules capable of multiphoton absorption in the near IR range. The nonlinear transmission property and output/input characteristics have been studied based on this liquid dye system, using nanoseconds 1.064-/spl mu/m laser pulses for two-photon excitation and /spl sim/1.3-/spl mu/m subpicoseconds laser pulses for three-photon excitation. A fairly good optical stabilization capability of this new material has been demonstrated at both laser wavelengths. The relative intensity fluctuation of the laser pulses can be remarkably reduced by simply passing through this multiphoton absorbing medium.     

闪光灯激励的染料激光振荡-放大系统

我们研制了一台闪光灯激励的染料激光器,由一具窄带振荡器和一级行波放大器组成。采用了气压调谐,使用R6G染料,脉冲功率超过30千瓦,线宽0.01～0.05埃,调谐精度优于0.004埃。     

以脉冲氙离子激光器为泵浦和注入光源的注入锁定染料激光器

描述了一个注入锁定的染料激光器,它是用脉冲氙离子激光器泵浦的若丹明6G四镜环形染料激光器,并且用氙离子激光输出线中的5960?作为注入光源、研究了注入锁定染料激光器的输出强度和光谱特性.     

Low threshold,room temperature pulsed and quasi-continuous lasing in optically pumped CdZnTe/ZnTe quantum wells

We report room temperature optically pumped lasing with a threshold of 6 kW/ cm² in a CdZnTe/ZnTe multiple quantum well. Quasi-continuous optically pumped lasing at room temperature has also been achieved. We discuss the influence of composition on mode confinement and show that the lowest thresholds are expected in samples in which the active layer is slightly zinc-rich compared to the cladding layers.     

闪光灯泵浦染料激光器PTM运转的能量转移特性

根据由速率方程导出的一组微分-积分方程,研究了闪光灯泵浦染料激光器PTM运转时的能量转移特性。比较了PTM运转和正常运转时能量转移过程的主要区别。给出了转移到受激辐射、非受激辐射、腔损耗、三重态吸收等方面的能量与腔内光子寿命的关系。     

354.7 nm的产生及其泵浦的可调谐染料激光器

用和频的方法从Nd:YAG激光器中产生出三次谐波,输出功率为1.7兆瓦,并用它泵浦了染料激光器。染料激光的波长可调谐范围为409.3～682.3 nm。Coumarin47染料的中心波长450.0 nm处的峰值功率大于0.60兆瓦。仅用Coumarin152一种染料,调谐范围宽达104.2 nm,与其荧光谱线宽度120.0 nm相近。     

Cascade lasing of molecular HBr in the four micron region pumped by a Nd:YAG laser

Due to a narrow window of high atmospheric transmission near 4 /spl mu/m there is a great deal of interest for a scalable laser energy source in this spectral region. We propose a concept combining the advantages of solid-state and gas laser technology. It takes advantage of a coincidence of a Nd:YAG laser line and an overtone transition of the molecule HBr. Tuning a Q-switched Nd:YAG laser to 1.3391 /spl mu/m allows us to excite the v(0 /spl rarr/ 3), J(4 /spl rarr/ 5) vibrational-rotational transition of HBr. To stabilize the pump frequency, a diode laser locked to this HBr transition seeds the Nd:YAG laser. Once excited, HBr can potentially lase in three subsequent steps to the ground state, two of which were observed experimentally, emitting up to three photons in the 4-/spl mu/m region. We present theoretical and experimental results demonstrating the operational principle of this laser system. The comparison of experiment and theory suggests: 1) that intracavity CO/sub 2/ can force the system to lase on only those transitions that are within the atmospheric transmission window, and 2) the existence of amplified spontaneous emission driven by pure rotational transitions.     

XeCl准分子激光泵浦的DCM-丙二醇碳酸酯染料激光体系的光谱和激光特性

测量了XeCl准分子激光泵浦的DCM-丙二醇碳酸酯染料激光体系的能量输出和光谱特性。所得结果表明,与DCM-二甲基亚砜染料体系相比较,它的能量转换效率较低,但调谐范围更宽。     

Doppler展宽的四能级系统无反转激光的传播效应

在考虑Doppler效应下,通过理论分析和数值模拟研究了传播效应对开放四能级系统中的无反转激光特性的影响.研究发现:探测场和驱动场同向传输对系统获得无反转激光更为有利,要想提高探测激光的增益不仅要选取合适的入口处驱动场Rabi频率值,而且选取适当的驱动场和探测场初始失谐值对于提高激光增益也极为关键;随传播距离的增大,探测场上下能级粒子数一直满足无反转,而探测场上能级和驱动场上能级间的粒子数随传播距离的增大发生了Raman反转.     

Probe beam amplification via two- and four-wave mixings in a nematic liquid crystal film

We have observed very large probe beam gain (up to 600 percent) in a thin film (100 μm) of nematic liquid crystal for a low pump beam intensity on the order of 2 W/cm². The effect is nonlinearly dependent on the pump intensity and the wave mixing angle.     

Recent progress in the development of electrically and optically pumped dye vapor lasers

This paper reviews new results in the field of organic dye vapor lasers. Gain studies of the scintillator dye POPOP in liquid solution and in the vapor phase show that a dye vapor exhibits optical gain nearly as high as in the solution case under excitation by a N2laser. Superradiant emission has been observed from both, optically excited POPOP vapor and electron-beam excited vapor. The optimum operating conditions of an electron-beam pumped dye vapor-buffer gas system with high purity argon as buffer are reported. Potential energy transfer processes from the rare-gas buffer to the dye vapor are discussed. The metastable ionic species Ar+2has been identified as the most likely POPOP excitation source after intense electron pumping of the dense Ar buffer gas at typically 4-5 atm. An estimate of the conversion efficiency from electronic energy deposited in the Ar buffer to stimulated emission of the dye yields 5 percent. These results suggest that an efficient tunable electron beam pumped dye vapor laser is feasible.     

主动锁模和调Q Nd:YAG激光倍频同步泵浦染料激光器特性研究

本文介绍一种主动锁模和调Q Nd:YAG激光倍频同步泵浦可调谐染料激光器。由此激光器已获得脉冲宽度为70ps,脉冲能量为0.1μJ,调Q重复率达7kHz,调谐范围为580～610nm的微微秒脉冲,本文还研究了这一激光器的时间和频谱特性,分析了腔长失配对脉宽和中心波长的影响。     

Temporal and spectral studies of a synchronously pumped dye laser: Detailed interpretation of autocorrelation measurements

With the combination of precise autocorrelation and spectral measurements we have established the influence of pulse substructure on the determination of pulse envelope duration of a synchronously pumped dye laser within the noise burst model of Pike and Hersher. Our results make a single sided exponential pulse shape unlikely and we present evidence supporting pulses having Gaussian or skewed Gaussian temporal profiles.     

对同步泵浦染料激光器系统已有实验结果的解释和讨论

给出的同步泵浦染料激光脉冲的理论结果作一些讨论和解释,特别是该理论证实的同步泵浦染料激光脉冲的宽度与功率均存在最佳值的问题。     

Distortion in single-, two- and three-stage amplifiers

Nonlinear distortion in single-, two-, and three-stage operational amplifiers (opamps) is the main scope of this paper. For each opamp, distortion contributions from different groups of transistors are identified and plotted versus frequency. This makes it possible to find the strongest sources of distortion in the various frequency regions. Further, equations that describe the third harmonic as a function of circuit parameters and input frequency are presented. Despite the simplifications, these equations describe the third harmonic accurately. Further, they provide insight and understanding by connecting distortion to circuit parameters such as transconductances, capacitances, poles, and zeros. The comparison of the opamps shows that each opamp has a frequency region where the distortion is lower than for the other two. The three-stage op amp has far lower distortion at low frequencies, the single-stage op amp is better at high frequency and the two-stage op amp is best for the mid frequency range.     

氩离子激光器声光主动锁模及同步泵浦连续波可调谐超短脉冲染料激光器

我们研究并改进了360型氩离子激光器输出功率和模式的稳定性,设计了适合于这种激光器的三转轴并有腔长延伸机构的声光锁模头。用频率稳定度为10~(-8)、频率步进为1赫的高性能频率综合器信号经射频功率放大器驱动拉曼-奈斯型声光棱镜,从而很好地解决了氩离子激光器腔长、调制器谐振频率以及驱动信号源三者之间的精确匹配,在此基础上研究了Ar~ 激光器腔内增益输出耦合率、调制深度以及腔长和频率失调等对锁模的影响。在工作参数选择适当时对5145(?)和4880(?)均可得到稳定可靠的锁模运转。用光二极管和取样示波器可看到稳定的锁模脉冲列,示波图半极大全宽～500微微秒(系统响应极限),脉冲峰功率起伏小于     

R6G和CV混合染料的激光辐射特性

详细考察了若丹明6G(R6G)和甲酚紫(CV)激光染料组成的二元乙醇溶液体系在532nm光泵浦下的激光辐射,讨论并分析了在不同浓度配比情况下分子间能量转移和激光辐射规律。     

Studies of photorefractive properties of a novel dye‐doped nematic liquid crystal system

We examine here photorefractive and dielectric properties of a novel system: nematic liquid crystal mixture doped with 1‐(5‐methylfuran‐2‐yl)‐3‐(4‐dimethylaminophenyl)‐propenon dye. Kinetics of formation of refractive index gratings induced by light in a two‐wave mixing experiment in this dye‐doped nematic liquid crystal together with dielectric relaxation and ionic conductivity are investigated. We perform a degenerate four‐wave mixing experiment, enabling us to observe the generation of an optical phase conjugation signal by the studied system, and report on some optical microscope observations of hydrodynamic instabilities related to charge injection from the electrodes and ionic current flow through liquid crystal layer. We discuss the results in reference to other similar liquid crystalline materials. Copyright © 2000 John Wiley & Sons, Ltd.     

同步泵浦染料激光器系统所产生的微微秒脉冲的特性——三阶增益展开的锁模方程及其解

本文提出了三阶增益展开锁模方程,并用Lagrange乘子法求解该方程,得到了同步泵浦染料激光脉冲的宽度、强度和延时(它是泵浦脉冲相对染料脉冲的提前量)的简单解析表达式,能够圆满解释目前已发表的某些实验事实。