FEMTOSECOND-PULSE CHARACTERIZATION: Novel 2DSI method measures sub-two-cycle laser pulses

摘要

A new pulse-characterization technique is designed for few- and single-cycle laser pulses. Called two-dimensional spectral shearing interferometry (2DSI), it has been demonstrated on sub-two-cycle 4.9 fs pulses centered at 800 nm. In the four decades since the first demonstration of laser modelocking, short-pulse laser technology has steadily progressed from nanosecond pulses to the point at which near-IR pulses shorter than 5 fs (less than two optical cycles) are regularly produced directly from tabletop lasers. Such precise creation of coherent light over more than 200 THz of bandwidth has opened up new areas of applied and fundamental physical research: pulses at this timescale allow for the probing of physical phenomena on a femtosecond timescale, sufficient to resolve electronic relaxation processes in molecules or bonding dynamics, and have coherent bandwidths sufficient to control molecular quantum states to guide reactions.