Sub-5-fs transform-limited visible pulse source and its applicationto real-time spectroscopy

摘要

Transform-limited (TL) visible pulses with as short a duration asn4.7 fs with a 5-ΜJ pulse energy have been generated for the firstntime from a novel noncollinear optical parametric amplifier. Bothnsignal-idler group-velocity matching and pulse-front matching arenessential to generate coherent down-converted pulses compressible to thenTL pulse with more than 150 THz bandwidth. Tunable operation withnbandwidth-limited sub-10-fs pulses in the visible (550-700 nm) andnnear-infrared (900-1300 nm) ranges, achieved by increasing the seednchirp, is also a marked property. Applications for ultrafastnspectroscopy of the sub-5-fs pulse source to the real-time spectroscopynof conjugated polymer, a dye molecule, and J-aggregates are alsondescribed