  Coherent scattering of an electron beam by the Kapitza-Dirac effect from a
standing laser wave which comprises two frequency components is studied. To
this end, the Schr\"odinger equation is solved numerically with a suitable
ponderomotive potential. Besides, an analytical solution for electron
diffraction in the asymptotic domain of large field amplitudes is obtained and
a mathematical model in reduced dimensionality for the scattering amplitude in
the Bragg regime is presented. We demonstrate distinct interference signatures
and relative phase effects when the standing wave contains a fundamental
frequency and its second harmonic. The influence of the relative field
intensities on the Rabi oscillation dynamics is also discussed.
