Quantum processes in a two-mode laser field

The probabilities of the emission of a photon by an electron and e(+)e(-)-p air photoproduction in a field which is a superposition of two electromagne tic plane waves with different frequencies and propagating in the same dire ction are obtained. The case where the frequencies of the two modes are com mensurate is studied in detail. This case is interesting primarily because of the existence of effects due to the interference of amplitudes, correspo nding to a different number of photons absorbed from different modes but ha ving the same total 4-momentum. It is shown that the optimal field for obse rving interference effects is a field such that the ratio of the mode frequ encies is 3. The probabilities of radiation and pair-photoproduction proces ses in the field of a monochromatic plane wave and in a two-mode field, obt ained by splitting the initial wave into two waves, are compared. It is sho wn that the total probability of the emission of a photon by an electron in a two-mode field is lower than and the probability of pair photoproduction is higher than the probabilities of the same processes in the initial wave . The increase in the pair-photoproduction probability is explained by the fact that additional channels for reactions which are forbidden in the init ial monochromatic field open up in a two-mode field. (C) 2000 MAIK "Nauka/I nterperiodica".