  We derive the current response to the linearly polarized electromagnetic
field with finite frequency and wave vector incident normally on the specular
surface of a clean nonconventional superconductor with orbital spontaneous
magnetization parallel to the crystal axis and perpendicular to the crystal
surface. The result includes the usual part known from the theory of
conventional superconductivity and as well the magneto-optical term typical for
the superconductors with spontaneous time reversal breaking. As an application
of the basic current-field relation we consider the Kerr effect for the
rotation of polarization of infrared light reflected from the superconductor
surface.
