Fig. 4: Comparison of 800-nm and 400-nm driven solid-state high-harmonic generation.
From: Enhancing the efficiency of high-order harmonics with two-color non-collinear wave mixing in silica
a Experimentally measured far-field wave mixing spectrum in silica with equal 400-nm and 800-nm intensities of 1.6 TW/cm2. b Simulated spectra, comparing 400-nm, 800-nm, and two-color driving pulses with equal intensity. c Electrons in the first conduction band as a function of time and crystal momentum for an 800-nm pulse (vector potential represented by the blue line), and d for a 400-nm pulse. e Energy- and momentum-resolved polarization for 800 nm, and f for 400 nm, both for an intensity of 1.6 TW/cm2. The color bar represents harmonic yield on a logarithmic scale. Harmonic orders refer to multiples of the 800-nm fundamental, with even orders of the driving frequencies canceling out in the emission spectrum due to symmetry.
