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 研究涉及开发和维护纳秒 吸收分光计 该设备继续提供高 质量频谱从纳秒到秒的时间尺度，具有宽 样品处理范围和改进的动力学分析软件。 的 一种仪器可以记录被激发的瞬变的吸收或增益谱 由20赫兹的YAG激光器发出的脉冲。 探测源是一个 氙闪光通过石英光纤传输到样品。 的 通过门控二极管阵列实现时间分辨率。 另外我们 我构建了一个瞬态吸收系统，该系统由两个 NdYAG激光器已被修改为“填充”光束轮廓。 此外，我们还采用了光学参量振荡器 (OPO)这双YAG设置产生近红外和中红外 频率，以探测过程，如蛋白质构象 动力学 这种OPO很容易产生足够的脉冲能量， 在25至300 ℃的水溶液中， 用于蛋白质折叠动力学测量的超快触发器。 耦合 该系统是染料激光器（由第二Nd：YAG激光器泵浦），其 输出可以加倍到270-300 nm;这用于泵浦荧光 芳香族氨基酸的转变。 荧光的变化 量子产率和？最大发射是敏感的探针， 蛋白质的构象变化，我们有能力 监控任何一处房产 该配置还将允许 用荧光产生的宽带光探测瞬态 染料，这将显着提高S/N的瞬态 光谱测量 一个皮秒系统， 放大的连续谱，适用于大范围的泵浦和探测 具有增加的重复率（在kHz域中）的波长是 正在开发中。 该系统可以耦合到双强化 二极管阵列检测系统，用于常规采集光谱， “用户友好”的基础。

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.