Distance Measurement in Air with a Femtosecond Frequency Comb Laser

Abstract

This thesis is about interferometric distance measurement using ultrashort pulses, with linear measurement techniques in a dispersive medium. Several fields of expertise are combined here: ultrashort pulse propagation in dispersive media, distance measurement interefometry and linear measurement techniques. All our measurements can be mainly classified into two interferometers we built as a part of this work. The two interferometers share somethings in common but also differs: They shared the same femtosecond laser source; both had 50 m long path length differences between the two arms. The detected signals from the two methods are quite different: one is cross correlations, with measured intensity as a time sequence, and the other is spectral interferograms, measured by a grating spectrometer. But the information obtained from the two detection methods are the same: The PSD and the path length difference at certain enviroment conditions.