Quasi-phase matching of high harmonics driven by mid-IR: toward the efficiency drop compensation

Abstract

This paper presents a detailed investigation of the high-order harmonics generation quasi-phase matching in a series of gas jets interacting with a two-color laser field formed by the fundamental and the second harmonics of a mid-IR laser source. A quadratic growth of the enhanced harmonics efficiency as a function of a laser wavelength is presented. A power growth of the enhanced harmonics efficiency as a function of the width of the gas jets is also demonstrated. A simple relation connecting the position of the enhanced harmonics and the macroparamaters of the gas jets is introduced. Physical mechanisms lying behind the observed phenomena are also discussed.