Wavelength scaling of high-order-harmonic-generation efficiency by few-cycle laser pulses: Influence of carrier-envelope phase

Abstract

We investigate the wavelength scaling of high-order-harmonic-generation (HHG) efficiency by few-cycle laser pulses where the influence of the carrier-envelope phase (CEP) becomes prominent. Based on the numerical solution of time-dependent Schr\"odinger equation, in the infrared region of $\ensuremath{\lambda}$ (0.8--1.8 $\ensuremath{\mu}$m), we observe that the power law of the form ${\ensuremath{\lambda}}^{\ensuremath{-}x}$ ($x\ensuremath{\approx}5$--6) is still present; but for constant intensity and a fixed energy interval, it differs markedly in the CEP. We find that for a specific value of CEP the wavelength dependence follows a ${\ensuremath{\lambda}}^{\ensuremath{-}4.6}$ scaling in high-harmonic yield. We also perform classical trajectory calculations to gain some understanding of the CEP dependence of the wavelength scaling.