2025/08/12 by Jessen, Simon P. S., Mero, Mark, Vrakking, Marc J. J. +3
#Atomic Physics (physics.atom-ph) #FOS: Physical sciences #Optics (physics.optics)
paper · doi:10.48550/arxiv.2508.09364
We investigate the nonlinear optical response of bulk ZnO under intense short-wave infrared excitation, focusing on the interplay between high-harmonic generation (HHG) and photoluminescence (PL). While HHG exhibits non-perturbative intensity scaling and a spectral blueshift consistent with plasma-induced refractive index changes, the PL signal shows a pronounced superlinear increase and a redshift, attributed to a combination of exciton-exciton scattering and phonon-assisted exciton recombination emission. A similar PL response under above-bandgap excitation supports its intrinsic origin. Spectral analysis of the HHG emission reveals an intensity-driven transition in the characteristics of the fifth harmonic, indicating a change in the underlying generation mechanism. These findings establish PL and spectral HHG analysis as complementary probes of strong-field and many-body effects in wide-bandgap semiconductors.