We introduce a spectral-interferometry (SI) technique for measuring the complete intensity and phase of relatively long and very complex ultrashort pulses. Ordinarily, such a method would require a high-resolution spectrometer, but our method overcomes this need. It involves making multiple measurements using SI (in its SEA TADPOLE variation) at numerous delays, measuring many temporal pulselets within the pulse, and concatenating the resulting pulselets. Its spectral resolution is the inverse delay range--many times higher than that of the spectrometer used. Our simple proof-of-principle implementation of it provided 71 fs temporal resolution and a temporal range of 100 ps using a few-cm low-resolution spectrometer.

We introduce and demonstrate a simple, compact, and automatically aligned ultrashort-pulse compressor that uses only a single diffraction element-a grating or a grism (a grating on a prism). This design automatically has unity beam magnification and automatically contributes zero spatiotemporal distortions to the pulse, thus avoiding spatial chirp, angular dispersion, pulse-front tilt, and all other first-order spatiotemporal distortions. It is comprised of only three elements: a diffraction element, a corner cube, and a roof mirror. Half the size of comparable two-grating compressors, it can provide large amounts of negative group-delay dispersion with small translations of the corner cube. The device can operate on pulses with both large and small bandwidths by varying the corner-cube position. Using a grism as the diffraction element, material dispersion up to the third order can be compensated, and we demonstrated compensation for 10 m of optical fiber for 800 nm pulses.

We demonstrate a simple self-referenced single-shot method for simultaneously measuring two different arbitrary pulses, which can potentially be complex and also have very different wavelengths. The method is a variation of cross-correlation frequency-resolved optical gating (XFROG) that we call double-blind (DB) FROG. It involves measuring two spectrograms, both of which are obtained simultaneously in a single apparatus. DB FROG retrieves both pulses robustly by using the standard XFROG algorithm, implemented alternately on each of the traces, taking one pulse to be "known" and solving for the other. We show both numerically and experimentally that DB FROG using a polarization-gating beam geometry works reliably and appears to have no nontrivial ambiguities.