Temporal characterization of broadband femtosecond laser pulses by surface third-harmonic dispersion scan with ptychographic retrieval.

We present a new, to the best of our knowledge, variant of dispersion scan (d-scan) based on surface third-harmonic generation (STHG) and a ptychographic algorithm tailored for full retrieval (amplitude and phase) of broadband laser pulses. We demonstrate the technique by temporally measuring and compressing few-cycle pulses with 7 fs and 2.5 nJ from a Ti:sapphire oscillator, using a sapphire window as the nonlinear medium. The results are in very good agreement with standard second-harmonic d-scan measurements based on a nonlinear crystal. The intrinsically broadband and phase-matching-independent nature of STHG make this technique very suitable for the characterization of ultrashort laser pulses over a broad wavelength range extending into the mid-infrared.

Simultaneous measurement of two ultrashort near-ultraviolet pulses produced by a multiplate continuum using dual self-diffraction dispersion-scan.

We present a new method based on self-diffraction dispersion-scan (SD d-scan) that enables the simultaneous measurement of two distinct ultrashort laser pulses in a region where they spatially and temporally overlap. This situation can arise when sampling and focusing two different spatial portions of a single inhomogeneous beam onto a medium. We demonstrate this new dual SD d-scan method by simultaneously characterizing two intense broadband ultraviolet pulses at 400 nm, with durations in the 10 fs range, originating from two different spatial portions of a beam produced by a multiplate continuum (MPC).

All-optical measurement of the complete waveform of octave-spanning ultrashort light pulses.

We demonstrate the complete temporal characterization of the optical waveform of visible near-infrared octave-spanning ultrashort laser pulses, using an all-optical, all-solid-state, and fully inline dispersion-scan device based only on second-harmonic generation.

Inline self-diffraction dispersion-scan of over octave-spanning pulses in the single-cycle regime.

We present an implementation of dispersion-scan based on self-diffraction (SD d-scan) and apply it to the measurement of over octave-spanning sub-4-fs pulses. The results are compared with second-harmonic generation (SHG) d-scan. The efficiency of the SD process is derived theoretically and compared with the spectral response retrieved by the d-scan algorithm. The new SD d-scan has a robust inline setup and enables measuring pulses with over-octave spectra, single-cycle durations, and wavelength ranges beyond those of SHG crystals, such as the ultraviolet and the deep-ultraviolet.