<title>Studies on the fine structure of interferometric autocorrelation of ultrashort pulse with femtosecond accuracy</title>

Abstract

The interference fringes of the interferometric second order autocorrelation curves with a peak-to-background ratio of 8:1 are measured and analyzed. The femtosecond pulses are from a colliding pulse mode locked dye laser (CPM). The autocorrelator and datum acquisition are all controlled by an IBM PC/XT computer with the software and hardware specifically designed in this work. The experimental results demonstrate that the oscillatory frequency of the fine structure within the 8:1 curves is dominantly determined by the oscillatory frequency of the interferometric autocorrelation of the fundamental wave. The curves are well fitted with the theoretical calculation for the interferometric autocorrelation trace for a hyperbolic-secant- squared pulse. The intensity autocorrelation curves are also measured. It is found that the optical delay line must be moved above a certain high speed, otherwise it is possible to get a wrong intensity autocorrelation curve and the measurement result will include some interferometric information.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.