Abstract by Nicholas Ellsworth
Chemistry and Biochemistry
Optical Fiber Based Single-shot Ultrafast Spectroscopy
Ultrafast pump-probe spectroscopy can be used to measure phenomena that occurs on the picosecond time scale. Single-shot spectroscopy is a novel technique that can speed up data-acquisition times by several orders of magnitude. In traditional pump-probe measurements, several hundreds to thousands of laser pulses are required to map out a trace. In single-shot measurements the response of the sample to the pump pulse is spectrally encoded onto a stretched probe pulse. This probe pulse is then focused into an optical fiber that acts to stretch the probe pulse from a few ps to the ns timescale. This pulse can then be readout by a fast photodiode onto an oscilloscope. Ideally an entire trace can be recorded with a single pulse from the laser system. A further advantage of single-shot measurements makes possible the recording of irreversible reactions; this can be utilized to study damage thresholds and phase changes in our samples. I will discuss tests of this fiber-based single shot method and compare our results to spectrometer-based measurements.