甲酚紫非线性光学性质的研究

报道了甲酚紫染料的非线性光学性质的实验研究方法及其结果.利用简并四波混频技术,测量得到甲酚紫甲醇溶液(浓度为5×10~(-4)M)的三阶非线性极化率X~(3)为2.0×10~(-10)esu.此外,利用不同强度皮秒脉冲相关技术得到了甲酚紫甲醇溶液的吸收恢复时间τ_(21)为163ps.     

用不同强度皮秒脉冲相关技术测量甲酚紫吸收恢复时间

以Ar+离子锁模激光器同步泵浦R6G染料激光器作光源,用不同强度皮秒脉冲相关的泵涌—探测技术测得甲酚紫甲醇溶液的吸收恢复时间为162±3.5ps.并且用三能级模型对这一动力学过程进行了理论分析.     

甲酚紫三阶非线性极化率的测量

甲酚紫(Cresyl Violet)是一种常用的有机染料。H.Telle和W.Huller测量出甲酚紫在乙醇溶液中(浓度为2.0×10~(-3)mol/1)的吸收峰值波长为613nm,半宽度为68nm。我们利用简并四波混频技术(DFWM)测量了甲酚紫的三阶非线性极化率X_(?)。实验结果表明,甲酚紫具有大的三阶光学非线性。     

染料分子电子激发态振动失相过程的非相干光时延四波混频研究

本文对噁嗪(Oxagine)、甲酚紫(cresyl violet)染料分子的吸收带和吸收边进行了非相干光时延四波混频(TDFWM-IL)的详细研究,得到了有关失相参量的数据,并利用非相干光时延四渡混频的多能理论解释了实验结果和失相参量的物理意义。     

新型红外超快速可饱和吸收染料的光谱及微微秒弛豫时间的测量

本文着重介绍了几种新型的稳定红外超快速可饱和吸收染料的光谱及其微微秒弛豫时间的测量.讨论了有关的实验技术.通过相关测量确定了小于1ps的系统时间分辨率.测得了四种染料的吸收恢复时间为5～9ps范围内的不同值.但光化稳定性明显地比Kodak染料好.     

苯酚磺酞类酸性染料与人血清白蛋白的结合

在人体条件下 ,用荧光光谱法研究了苯酚磺酞类酸性染料苯酚红、甲酚红、氯酚红、溴甲酚紫、间甲酚紫与人血清白蛋白 (HSA)之间的相互作用。实验表明 :苯酚磺酞类酸性染料对人血清白蛋白的荧光有较强的猝灭作用 ,其荧光猝灭主要为静态猝灭 ,从荧光猝灭结果求得不同温度下各染料与HSA的结合常数K ,发现染料取代基的引入使K值增大 ,且随反应温度上升K值下降。由染料与HSA反应焓变、熵变 ,确定染料与HSA的结合主要是静电引力。依据非辐射能量转移机理 ,探讨了不同温度下该类染料与HSA相互结合时 ,其给体 受体间距离和能量转移效率。进一步证实了该类反应为单一静态猝灭过程 ,且阐明了其猝灭机理是通过能量转移产生的。     

罗丹明101染料的光谱特性研究

观测了罗丹明101染料在甲醇和酸性甲醇溶液巾的稳态吸收、稳态荧光和时间分辨荧光光谱,得到了吸收与荧光光谱的特征信息以及荧光寿命;通过拉曼光谱、红外光谱和密度泛函理论计算,对罗丹明101染料分子的振动模式进行了指认.研究结果全面系统地表征了罗丹明101染料的光谱特征以及分子结构和振动信息,为罗丹明101染料在染料敏化太阳能电池和生物荧光标记等方面的应用研究提供了依据.     

极性染料溶液的微微秒动态荧光光谱移位

本文测量了染料分子DCM、甲酚紫、DODCI和DTDCI在极性溶剂中的微微秒时间分辨荧光光谱;作者将动态的光谱移位归结为由于溶质分子激发态与基态偶极矩的显著差异而引起的周围溶剂分子的介电弛豫;并从动态的光谱移位得到的弛豫时间很接近由连续腔体理论模型求得的计算值,表明连续胜体模型用于描述动态的光谱移位现象是适用的.     

飞秒激光脉冲产生研究

本文通过对被动锁模染料激光器锁模动力学特性分析,讨论了对撞脉冲锁模(CPM)环型染料激光器产生持续期为10~(-12)秒到10~(-15)秒量级的高稳定度光脉冲的锁模机理。选择有大吸收,发射截面和很短恢复时间的R6G增益介质和有更大吸收截面的DODCI可饱和吸收体,能够获得极短的光脉冲。为获得几十飞秒光脉冲的稳定运     

BDN染料光吸收的饱和效应的实验

<正> 一、引言近年来BDN染料及染料片在国内相继研制成功。为了进一步认识这种染料的性能及工作机制,我们测试了BDN染料的饱和光强与剩余吸收;并对其激发态寿命、激发态吸收等问题进行了讨论。     

用锁模超短脉冲串直接测量BDN染料的恢复时间

使用激发探测技术测定了在二氯乙烷和碘乙烷溶液中有机染料BDN的基态恢复时间,实验中整个脉冲串的积分透射是作为激发、探测脉冲间延迟时间的函数测定的。所用的脉冲串是由被动锁模的Nd:YAG激光器产生的。实验结果与可漂白染料三能级模型速率方程的解相一致。 关键词：     

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.     

Picosecond fluorescence studies by intracavity gain spectroscopy in a modelocked dye laser

This article presents measurements which combine modelocking technique with intracavity spectroscopy. To test this approach, a sample (10^–5 m ethanolic solution of 1,4-dihydroxyanthranquinone) was inserted in a modelocked Ar⁺ ion laser and probed by intracavity pulses of a synchronously pumped dye laser. The probing of the sample results in an amplification of the dye laser output. Maximum output was measured if the pulses of the dye laser temporally overlapped with those of the Ar⁺ ion laser inside the sample. Under this condition, the spectral laser intensity was shaped by the spectrum of stimulated fluorescence which originated from a molecular vibronic state populated by pump laser excitation.Presented at LASERION '91, June 12–14, 1991, München (Germany)     

Numerical calculations of intracavity dye Q-switched ruby laser

A mathematical model describing the dynamic emission of the Q-switched ruby laser has been adapted. The suggested model allows the investigation of the effects of a dye cell on the mode characteristics of the ruby laser and, moreover, the study of the effect of the laser input parameters on the output laser pulse. This model simulates the nonlinear effects of dye pulse modulation on the laser emission.In addition, a numerical solution of a nonlinear rate equation system of the adapted model is discussed. The solution estimates the density of the emitted radiation, population inversion and energy transfer processes of the ruby laser rod and dye cell for different emission regimes (one pulse regime, free running pulses, repetition periodic pulses). The estimated results of the laser output pulse characteristics are in a good agreement with the other calculated and experimental results.     

Subpicosecond UV pulse generation for a multiterawatt KrF laser

A 180-fs UV pulse has been generated based on a hybrid synchronously pumped mode-locked dye laser for a multiterawatt KrF laser system. The pulse width was measured by the single shot autocorrelation technique with the three-photon fluorescence of the XeF C-A transition. The pulse width broadening due to dispersive media was investigated. The results show that the observed pulse width broadening from 210 fs to 390 fs through the entire system is explained mostly by the linear dispersion of the optical elements for near-transform-limited input pulses.     

Combination of high-intensity femtosecond laser pulses for generation of time-dependent polarization pulses and ionization of atomic gas

Time-dependent polarization pulses are generated by combining two perpendicularly polarized, high-intensity laser pulses. The time evolution of the polarization state of the combined laser pulse is measured by the POLLIWOG technique. We observed changes in the polarization state while varying the relative delay. In order to investigate the effect of pulse combination on the ionization of atoms, the electron signals and the ion signals are measured by irradiating combinations of two perpendicularly polarized pulses or two parallel polarized pulses. With the two parallel polarized pulses, high-order fringe-resolved autocorrelations are obtained by measuring the time-integrated ion signals as a function of the time delay. When two perpendicularly polarized pulses are combined, the fringe period of the time-integrated electron signal as a function of the time delay is different from that of the time-integrated ion signal. This is due to the fact that the electron signal depends on the direction of the field vibration and the number of generated electrons. We also measured the electron energy distributions at different relative delays and confirmed that these depend on the polarization state of generated pulses.     

Pulse properties of a synchronously mode-locked,cavity dumped,picosecond dye laser system

A synchronously mode-locked, cavity-dumped picosecond dye laser is described. The structure and intensity of the picosecond pulses measured under different conditions are reported. It was found that the structure of the pulses from the synchronously pumped dye laser depends critically on the length of the Ar⁺ laser pulses. At the shortest Ar⁺ laser pulses of about 70 ps the dye pulses are as short as 1.1 ps. With Ar⁺ laser pulses of 200 ps the dye laser pulses contains a broad satellite pulse which contains a large fraction of the total intensity. When a cavity dumper is added to the system one gets dye laser pulses 15–20 ps long with a substructure, which indicates incomplete mode-locking. Well mode-locked 1.5–2.0 ps pulses were obtained in the red part of the dye laser action spectrum, i.e. 620–650 nm for R6G, 595–608 nm for R 110 and 657–662 nm for RB, respectively. Addition of mode-locking dyes also improved the pulse quality at some wavelengths.     

Passive compression of KrCl excimer laser pulses in naphthalene solutions

The width of KrCl laser pulses has been compressed from 5.2 ns to less than 800 ps using naphthalene as the saturable absorber dye. It was found that the width of the compressed laser pulse decreased with both the input laser intensity and the concentration of naphthalene in the solution. The pulse shortening mechanism is attributed to excited state S₂-S_n transitions in naphthalene.     

Ultrahigh-resolution coherence spectroscopy by means of periodic excitation with picosecond pulses

The feasibility of ultrahigh-resolution coherence spectroscopy with a train of picosecond light pulses from a synchronously pumped mode-locked and cavity-dumped dye laser is demonstrated. Narrow resonances of periodic pulse excitation are observed whenever the pulse repetition rate of the laser of a higher harmonic coincides with the frequency splitting of coherently excited levels. The zero-field hyperfine splitting of the Na-ground state (1771.6 MHz) could be measured in the 2100th order of the excitation rate with a resonance halfwidth of 800 Hz.     

Measurement of atomic lifetimes with a mode-locked laser

We present a new technique for measuring atomic lifetimes with a mode-locked laser. A single laser pulse excites the atoms and a subsequent frequency-doubled pulse ionizes the excited-state atoms. The ions are collected and counted. The measurement is repeated using excitation and detection pulses with different time separations, which determines the excited-state decay rate. We demonstrated this technique for the 6P(3/2) state of cesium. The measured lifetime was 30.5 ns and had a statistical uncertainty of 0.1 ns. Systematic effects limited the overall experimental uncertainty to approximately 0.6 ns in this initial experiment.