Abstract

Intensity profile of ultrashort (ps and fs) pulses is only the part of information necessary in the analysis of propagation effects and light-matter interaction. Spectral information (phase modulation, instantaneous frequency, spectral distribution, chirp, etc.) is the other part required in the characterization of pulses. Nonlinear pulse-width meter such as noncollinear second harmonic generator, is successfully used in measuring pulse envelope in ps and fs scale.¹ The idea to combine noncollinear meter with the spectrograph was realized in FROG technique² where the whole (intensity and phase) temporal profile of pulse were retrieved. In our paper³ we have shown that in the pulsewidth meter based on noncollinear second harmonic generation the spectral information of pulse is presented in second-harmonic beam divergence. In the present paper we show that in the pulsewidth meter based on self-diffraction process (used in FROG technique) the divergence of self-diffraction beams contains enough spectral information to restore the chirp of pulses.

© 1994 IEEE