  We develop a theory of electron-photon interaction for helical edge channels
in two-dimensional topological insulators based on zinc-blende-type quantum
wells. It is shown that the lack of space inversion symmetry in such structures
enables the electro-dipole optical transitions between the spin branches of the
topological edge states. Further, we demonstrate the linear and circular
dichroism associated with the edge states and the generation of edge
photocurrents controlled by radiation polarization.
