Fig. 2: Modulation of the high harmonic distribution by the THz field.
From: High-order harmonic generation from a thin film crystal perturbed by a quasi-static terahertz field
a Typical high-order harmonic spectra without (shaded blue) and with (red line) the THz field. b The difference spectrum from a, i.e., ∣Y − Y0∣, here Y and Y0 are harmonic yields with and without the THz field, respectively. Absolute values are taken to plot the difference spectrum on log-scale, red and blue colors are used to distinguish the enhancement (Y > Y0) and suppression (Y < Y0) of the yield. For reference, the shaded gray is the spectrum without the THz field. c Blue: the relative suppression of odd-order harmonic, 1 − Y/Y0, red: the even-order harmonic yield relative to adjacent odd-orders, 2*Y2n/(Y2n−1 + Y2n+1), as a function of the harmonic order, at IMIR = 0.41 TW cm−2 and ITHz = 1.08 GW cm−2.
