NANOSECOND & PICOSECOND TRANSIENT SPECTROSCOPY

纳秒光谱学已经证明了广泛的

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 carried to the sample with an optical fiber. The time resolution is achieved by a gated diode array. In addition, we have constructed a transient absorption system which is run with two Nd:YAG lasers with filled-in beam profiles. This configuration will allow for probing of transients with broadband light generated from fluorescent dyes which will significantly improve the S/N of the transient spectral measurements. In addition, we have added an optical parametric oscillator into this dual YAG setup which will generate near and mid-IR frequencies in order to probe processes such as protein conformational dynamics. 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.