Characterization of high-order harmonics generated from solid surfaces

This paper aims to numerically and experimentally study optical harmonic generation from solid fused silica targets. 1D particle-in-cell (PIC) simulation and pump-probe femtosecond technique are used to characterize the spectral, spatial, and temporal properties of the high-order harmonics. PIC code indicates that it is quite feasible that surface harmonics generated at laser intensities of 10
²⁰
W/cm
²
can produce a train of or even single attosecond pulses in the 20-70 eV spectral range.