Spectral Phase Characterization of Two-Octave Bandwidth Pulses by Two-Dimensional Spectral Shearing Interferometry Based on Noncollinear Phase Matching With External Pulse Pair

Noncollinear phase matching with an external powerful reference pulse pair and an extremely broadband pulse to be measured in two-dimensional spectral shearing interferometry enabled us to characterize its spectral phase over the so-far broadest wavelength range from 328 to 1363 nm. The method has the additional advantage of the shorter measurement time (10 s) and higher sensitivity (at least 100 times) compared to conventional modified spectral-phase interferometry for direct electric-field reconstruction. This result exceeding two octaves suggests a possibility of the first generation of a single subcycle pulse in the ultraviolet to near-infrared region by the application to the feedback chirp compensation of the induced phase-modulated pulse with the use of a recently developed spatial light modulator with an over-two-octave bandwidth.