<title>Strong increase in the efficiency of high-order harmonic generation using counter-propagating laser pulses</title>

Abstract

We present results of computer simulations showing dramatic increases in the production and intensity of high-order harmonics (in the cutoff region) in rare gases interacting with counter-propagating pulses. Using two different models of medium, classical anharmonic oscillators (for Ne, Ar, Kr) as well as quantum oscillators (for Ne<SUP>+</SUP>, Ar<SUP>+</SUP>, Kr<SUP>+</SUP>), we demonstrate the increase of efficiency by four and by six orders in these models, respectively. This is at least by two orders of magnitude more than obtained with other methods.