| Popis: |
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. |
