NANOSECOND & PICOSECOND TRANSIENT SPECTROSCOPY

纳秒光谱学已经证明了广泛的 在整个生物学领域的应用。它允许识别 光触发过程中的中间物种。这 研究涉及纳秒的开发和维护 吸收光谱仪。该设备继续提供高性能 质量光谱从纳秒到秒的时间尺度，具有广泛的 样品处理的范围和改进的动力学分析软件。这个 可以记录激发的瞬变的吸收或增益谱的装置 通过运行在20赫兹的YAG激光器的脉冲。探测源是一个 氙气闪光通过石英光纤传输到样品。这个 时间分辨率由选通二极管阵列实现。此外，我们 已经构建了一个由两个人运行的瞬时吸收系统 经过“填充”光束轮廓修改的NdYAG激光器。 此外，我们还集成了一个光学参量振荡器 (OPO)进入此双YAG设置，可生成近IR和中IR 为了探测蛋白质构象等过程的频率 动力学。这种OPO很容易产生足够的脉冲能量来产生 温度在25到300摄氏度的水溶液中跳跃，起到了 用于蛋白质折叠动力学测量的超快触发器。耦合 到这个系统的是一个染料激光器(由第二个Nd：YAG激光泵浦)，它 输出可以加倍到270-300 nm；这被用来泵浦荧光 芳香氨基酸的转变。荧光技术的变化 量子产额和最大发射能是灵敏的探测器 蛋白质的构象变化，我们有能力 监控两处房产中的一处。此配置还将允许 利用荧光产生的宽带光探测瞬变 其中染料会显着提高S/N的瞬变 光谱测量。一个皮秒系统，将产生稳定的 用于大范围泵浦和探测的放大连续谱 具有增加的重复频率的波长(在KHz域中)是 正在开发中。这个系统可以耦合到双重强化 一种用于常规光谱采集的二极管阵列探测系统 “人性化”的基础上。

Nanosecond spectroscopy has demonstrated a wide range of applications over the whole of biology. It permits the identification of intermediate species in optically triggered processes. This research involves the development and maintenance of a nanosecond absorption spectrometer. This device continues to provide high quality spectra from the nanosecond to second time scale, with a wide range of sample handling and improved kinetic analysis software. The apparatus can record absorption or gain spectra of transients excited by pulses from a YAG laser running at 20Hz. The probe source is a xenon flash transmitted to the sample with quartz optical fibers. The time resolution is achieved by a gated diode array. In addition, we have constructed a transient absorption system which is run with two NdYAG lasers which have been modified for "filled-in" beam profiles. In addition, we have incorporated an optical parametric oscillator (OPO) into this dual YAG setup which generates near and mid-IR frequencies in order to probe processes such as protein conformational dynamics. This OPO easily generates enough pulse energy to produce temperature jumps in aqueous solution of 25 to 300C, acting as an ultrafast trigger for protein folding dynamics measurements. Coupled to this system is a dye laser (pumped by second Nd:YAG laser) whose output can be doubled to 270-300 nm; this is used to pump fluorescent transitions in aromatic amino acids. The change in fluorescent quantum yield and ?max for emission are sensitive probes of conformational changes in protein and we have the capability of monitoring either property. This configuration will also allow for probing of transients with broadband light generated from fluorescent dyes which will significantly improve the S/N of the transient spectral measurements. A picosecond system which will generate stable amplified continuum for a wide range of pumping and probing wavelengths with an increased repetition rate (in the kHz domain) is being developed. This system can be coupled to the dual intensified diode array detection system for routine acquisition of spectra on a "user-friendly" basis.