Angular Dispersion Boost of High Order Laser Harmonics Interacting with Dense Plasma Clusters

Abstract

Diffraction gratings and photonic crystals are widely used to control light. However, their capabilities are less effective in the case of extreme ultraviolet (XUV) radiation due to the high absorption of the optical material in this frequency range. In this work, we study the possibility of enhancing the angular dispersion of XUV radiation due to scattering by plasma clusters whose dimensions are smaller than the incident radiation wavelength. An analytical model was developed using the plasma Drude dielectric function and the Mie scattering theory in the quasi-static approximation. The resonant parameters of the target for the tenth harmonic of the Ti:Sa-laser are determined, and a significant enhancement of the scattered field in this case compared to the laser one is shown. Under resonance conditions for one cluster, the diffraction of radiation by an array of such clusters is simulated using the CELES code. The results obtained show a significant enhancement of the scattered field in the resonance case for large angles corresponding to the theory of Bragg–Wulf diffraction, which makes it possible to control high harmonics of laser radiation in the XUV range using ionized cluster gas.