Ultrafast semiconductor differential transmission spectroscopy with broadband chirped pulses

Summary form only given.We demonstrate experimentally that chirping of broadband 15-fs pulses has drastic effects on the differential transmission (DT) response of bulk semiconductors for excitation well above the bandgap. In particular, the rise and the initial fast decay of the spectrally integrated (SI) DT response and the shape of DT spectra are modified by chirp in an unexpected way. These new results have an impact on both fundamental studies and ultrafast switching applications as, for example, mode locking of solid-state lasers. Experiments were performed on a 200-nm thick Al/sub 0.06/Ga/sub 0.94/As sample at 300 K.