Application of Quasi-Phase Matching Concept for Enhancement of High-Order Harmonics of Ultrashort Laser Pulses in Plasmas

Abstract

Novel methods of coherent short-wavelength sources generation require thorough analysis for their further amendments and practical implementations. In this work, we report on the quasi-phase matching (QPM) of high-order harmonics generation during the propagation of single- and two-color femtosecond pulses through multi-jet plasmas, which allows the enhancement of groups of harmonics in different ranges of extreme ultraviolet. The role of the number of coherent zones; sizes of plasma jets and the distance between them; plasma formation conditions, and the characteristics of the fundamental radiation on the harmonic efficiency at quasi-phase matching (QPM) conditions are analyzed. We demonstrate the ~40× enhancement factor of the maximally-enhanced harmonic with respect to the one generated at ordinary conditions in the imperforated plasma.

Quasi-phase matching of harmonics generating in laser plasmas: experiment and theory

“…In this paper, we extended our latter investigations [7] to the study of the QPM in multijet indium plasma. We have experimentally and numerically demonstrated the enhancement of the group harmonics yield for which conditions of QPM became most favorable.…”

“…[6]. Recently, the model was applied to study the QPM conditions in perforated silver plasma [7]. In this paper, we extend the latter research by focusing in comparing conditions of QPM in indium multi-jet plasmas.…”

“…The details of experimental setup and the parameters of the experimental conditions are presented in Refs. [7].…”

“…1. Raw images of harmonic spectra from indium MJP with the single plasma jet sizes of (top to bottom) 0.23, 0.28, 0.31 mm pumped by two-color pulses: a) experiment [7], b) calculation.…”

High harmonics generation in gases near the gratings: towards the spectrum enhancement and enrichment

“…In the frame of the interference model the response of extended gas is simulated as a sum of single atoms forming the chain oriented along the laser field propagation direction, the photoemission responses of atoms are calculated in the frame of non-perturbative model [11]. The model was recently used to study of high harmonics generation enhancement due to the quasi-phase matching (QPM) effects in laser plasma, at least quantitate coincidence between experimentally measured and numerically calculated peculiarities of generated spectra was observed [12]. The model of neon atom energy structure that has been used to calculate single atom response was discussed in [13].…”