On the possibility of increasing the intensity of high-order harmonics dueto stimulated emission

We propose a new method for the amplification of high-order harmonics of la ser radiation based on stimulated emission accompanying the propagation of a probe pulse of a high-order harmonic through a gas medium irradiated by a high-power pump wave. It is demonstrated that such an amplification become s noticeable in the case when a probe wave of a high-order harmonic enters the interaction area with some delay time with respect to the pump wave. Ou r estimates for the gain of high-order harmonics show that this gain is pro portional to the delay time, reaching unity even for rather short delay tim es (corresponding to several optical cycles of the pump wave).