Increasing the efficiency of high-order harmonic generation using counterpropagating laser pulses

Abstract

We present results of computer simulations showing dramatic increases in the production and intensity of high-order harmonics ~in the cutoff region! produced by 20-fs pulse with counterpropagating pulse in rare gases. Using two different models for the gas medium ~i.e., classical anharmonic oscillators representing Ne, Ar, Kr and quantum oscillators representing Ne1, Ar1, Kr1), we demonstrate an efficiency increase of four and six orders of magnitude for the respective models. This suggests a notable improvement over other methods.