WAVEPACKET DIAGNOSIS WITH CHIRPED PROBE PULSES

For linearly chirped probe pulses, the observable pump-probe signal ca n be obtained analytically under useful idealizations: Gaussian packet and pulse, linear chirp, linear difference potential, and constant wa vepacket group velocity within the probe window. These conditions allo w the expression of the signal as a cross correlation between packet a nd probe window traveling in coordinate space at velocities upsilon an d upsilon(1), respectively. The signal delay and its integrated area a re independent of chirp. Relative to zero-chirp, the signal is tempora lly compressed for 0 < upsilon/upsilon(1) < 2, and becomes a minimum w hen packet and window co-propagate, upsilon = upsilon(1). Experimental data are used to illustrate wavepacket diagnosis in a real system. (C ) 1998 Elsevier Science B.V. All rights reserved.