Nanoengineering of strong field processes in solids

Abstract

We present a theoretical investigation of the effect of quantum confinement on high harmonic generation in semiconductor materials by systematically varying the confinement width along one or two directions transverse to the laser polarization. Our analysis shows a growth in high harmonic efficiency concurrent with a reduction of ionization. This decrease in ionization comes as a consequence of an increased band gap resulting from the confinement. The increase in harmonic efficiency results from a restriction of wave packet spreading, leading to greater recollision probability. Consequently, nanoengineering of one and two-dimensional nanosystems may prove to be a viable means to increase harmonic yield and photon energy in semiconductor materials driven by intense laser fields.

High-order harmonic generation in imperfect crystals

“…With increasing harmonic order, the intensity of intraband HHG decreases and interband HHG becomes dominant when going into the above-BG regime, resulting in a spectral minimum in the sub-BG region (of order ∼8) and a spectral maximum around the BG energy (of order ∼20). Such spectral features have also been observed in some other works using different methods [29,43]. For the system without disorder, the HHG spectrum has two plateaus, with their corresponding cutoffs of order ∼50 and ∼140, respectively.…”

Roadmap on photonic, electronic and atomic collision physics: I. Light–matter interaction

“…But solids also give us an ability to shape materials [68]. Quantum wells, quantum wires, or structured surfaces will allow us to control the electron trajectory, and therefore, to control the efficiency of harmonic conversion [69]. It is even possible to add nano-plasmonic antennas to a solid [70] to significantly decrease the required illuminating power, thereby bringing high-harmonic generation from high bandgap materials within reach of mode-locked oscillators, while also linking high-harmonic generation to modern research on meta-materials.…”

Visualization of the Preacceleration Process for High-Harmonic Generation in Solids

“…However, until now, HHG in solids has exhibited many unique and unexplored characteristics [27][28][29], and the underlying physics of HHG in solids has not been fully understood. At present, it is widely accepted that HHG in solids comes from two major contributions: intraband current and interband polarization [30][31][32]; the complex coupling between the two mechanisms not only affects the charge injection from the valence band to the conduction band but also affects the motion of excited-state electron wave packets in momentum space [33][34][35][36][37][38][39][40].…”