Femtosecond-resolution pulse-front distortion measurement by time-of-flight interferometry

The pulse-front distortion occurring in lenses and lens systems has been measured by a Michelson interferometer. In this technique the plane pulse front from one arm of the interferometer is used as a temporal reference level to map contour lines of equal propagation time on the pulse-front surface. The experimental arrangement is capable of detecting pulse-front distortion with a resolution of 20 fsec, and this can be improved to approximately 1 fsec. The measured value of pulse-front distortion in a telescope (1.1 psec) is in good agreement with the calculated data.