  We examine theoretically the intersubband transitions induced by laser beams
of light with orbital angular momentum (twisted light) in semiconductor quantum
wells at normal incidence. These transitions become possible in the absence of
gratings thanks to the fact that collimated laser beams present a component of
the light's electric field in the propagation direction. We derive the matrix
elements of the light-matter interaction for a Bessel-type twisted-light beam
represented by its vector potential in the paraxial approximation. Then, we
consider the dynamics of photo-excited electrons making intersubband
transitions between the first and second subbands of a standard semiconductor
quantum well. Finally, we analyze the light-matter matrix elements in order to
evaluate which transitions are more favorable for given orbital angular
momentum of the light beam in the case of small semiconductor structures.
