PHASE-DEPENDENT ON-SHELL AND OFF-SHELL EFFECTS IN REFLECTION OF ELECTRONS FROM AN IMPENETRABLE POTENTIAL WALL IN A BICHROMATIC LASER FIELD

We consider the reflection of electrons by an infinitely high potentia l wall in the presence of a bichromatic laser field having two compone nts of frequency omega and 2 omega. Both components are out of phase b y an angle phi. We evaluate the induced and inverse bremsstrahlung for this elementary scattering process and we discuss the coherent phase- control of the non-linear currents j(n; phi) of electron reflection. I f E(0) is the initial electron energy and ($) over bar h omega the pho ton energy, two specific cases will be of interest: (a) E(0) much grea ter than ($) over bar h omega and (b) E(0) greater than or similar to ($) over bar h omega, where in the latter case off-shell effects are p articularly relevant. We shall relate our findings to the correspondin g scattering of electrons by a hard sphere in a bichromatic field.