Ponderomotive shearing for spectral interferometry of extreme-ultraviolet pulses

Ultrabroadband spectral amplitude modulation using a liquid crystal spatial light modulator with ultraviolet-to-near-infrared bandwidth

The first demonstration to our knowledge in the spectral range from 300 to 1100 nm is presented for the amplitude modulation characteristics of a two-channel 648-pixel liquid crystal spatial light modulator. The broadest spectral amplitude modulation for UV (380-420 nm) and visible-to-near-IR (500-900 nm) pulses to generate a spectral-shifted pulse pair is experimentally realized. The results show that the liquid crystal spatial light modulator has a potential application for attosecond extreme-UV pulse characterization with the conventional SPIDER algorithm and the capability to shape monocycle optical pulses.

High harmonic XUV spectral phase interferometry for direct electric-field reconstruction

We demonstrate the first experimental complete temporal characterization of high-harmonic XUV pulses by spectral phase interferometry, with an all-optical setup. This method allows us to perform single-shot measurements of the harmonic temporal profile and phase, revealing a remarkable shot-to-shot stability. We characterize harmonics generated in argon by a 50 fs 800 nm laser pulse. The 11th harmonic is found to be 22 fs long with a negative chirp rate of -4.8 x 10(27) s(-2). This duration can be reduced to 13 fs by modulating the polarization of the generating laser. The technique is easy to implement and could be routinely used in femtosecond XUV pump-probe experiments with harmonics.