A computer simulation code to treat atomic excitation and laser beam propagation simultaneously in an atomic laser isotope separation system has been developed. The three-level Bloch-Maxwell equations are solved numerically to analyze the change of pulse shapes, the modification of laser frequencies and the time-varying atomic populations. The near-resonant effects on the propagation of frequency chirped and non-chirped laser pulses have been analyzed. It was found that there are serious differences in pulse shapes, frequency modifications and propagation velocities between laser pulses with and without chirping.

Ultrafast response of the diffraction efficiency of a photorefractive multiple quantum well (PRMQW) has been investigated by pump-probe spectroscopy. We evaluated the temporal evolution of the diffraction efficiency of the PRMQW using a differential transmission spectrum. The results were compared with the output-widening factor of diffracted pulses. A good agreement obtained between our evaluation results and the results of electric-field cross correlation has confirmed the applicability of our technique in characterizing the diffraction efficiency of the PRMQW.

Ultrafast response of the diffraction efficiency of a photorefractive multiple quantum well (PRMQW) has been investigated by pump-probe spectroscopy. We evaluated the temporal evolution of the diffraction efficiency of the PRMQW using a differential transmission spectrum. The results were compared with the output-widening factor of diffracted pulses. A good agreement obtained between our evaluation results and the results of electric-field cross correlation has confirmed the applicability of our technique in characterizing the diffraction efficiency of the PRMQW.