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Abstract

The rapid progress of short pulse laser technology has provided a concomitant increase in the use of ultrashort lasers for the characterization of the optical and electronic properties of semiconductor nanostructures and devices. As the characteristic timescale of the phenomenon under investigation approaches the optical pulse width that is used, it becomes increasely important to be able to fully characterize the amplitude and phase of the pulses before and after interacting with a sample in any given experiment. Towards this end, we designed and developed a computerized optical interferometric cross-correlator for femtosecond time-resolved laser spectroscopy, which can be used to extract amplitude and phase information from pulses used to probe a variety of systems. This electro-optical system, which we refer to as the rapid scan interferometric cross correlation system (RICCS), consists of a femtosecond Ti: sapphire laser source, a custom Mach- Zehnder interferometer for cross correlations, a continuous wave (cw) HeNe laser and a Michelson interferometer for relative path delay decoding, linear optoelectronic detection, electronic processing, computerized device control, and signal acquisition and data analysis. A novel aspect of this system is the use of a mirror mounted on an audio speaker as a rapid scanner to provide the relative path delay between the reference beam and signal beam in the Mach-Zehnder interferometer. Interferograms with up to 500 fringes each scan can be acquired by the computer at rates up to 25 scans per second. This thesis describes the principles of the operation of this RICCS system, its implementation, and its use in both auto-correlation and cross correlation modes.