High-dynamic-range pulse-front steepening of amplified femtosecond pulses by third-order dispersion

Abstract

Pulses of 25-fs duration from a Ti:sapphire multipass amplifier system have been temporally characterized over a high dynamic range with autocorrelation based on third harmonic generation. The investigated high-order-dispersion-controlled kHz system produces millijoule-energy 25-fs pulses with a symmetric intensity envelope which decreases by five orders of magnitude at a delay of 300 fs. The low-intensity wings of the pulse result from residual dispersion of fifth and higher order. Further steepening of the leading edge of these high-contrast femtosecond pulses over a dynamic range of five orders of magnitude has been achieved by introducing appropriate amount of third-order dispersion with specially designed chirped multilayer mirrors. © Springer-Verlag 1999.