Characterization of 20-fs VUV pulses by plasma-mirror frequency-resolved optical gating

Opt Lett. 2019 May 1;44(9):2282-2285. doi: 10.1364/OL.44.002282.

Abstract

We demonstrate that vacuum ultraviolet (VUV) pulses (λ∼160 nm) with 20-fs duration can be fully characterized by plasma-mirror frequency-resolved optical gating. Plasma is formed as an ultrafast optical switch on a fused silica surface by irradiation of an intense near-infrared (NIR) femtosecond laser pulse. We measure the spectra of the VUV pulses reflected off plasma as a function of the delay with respect to the NIR pulse and reconstruct it to simultaneously extract a nearly Fourier-transform limited VUV pulse shape and a time-dependent reflectivity of plasma using the least-squares generalized projections algorithm. We show that there is almost no spatial dependence of the VUV pulse shape, whereas the plasma mirror reflectivity strongly depends on the spatial region.