  In conventional Kerr- and Faraday microscopy the sample is illuminated with
plane-polarised light and a magnetic domain contrast is generated by an
analyser making use of the Kerr- or Faraday rotation. In this paper we
demonstrate possibilities of analyser-free magneto-optical microscopy based on
magnetisation-dependent intensity modulations of the light: (i) The transverse
Kerr effect can be applied for in-plane magnetised material, demonstrated for
an FeSi sheet. (ii) Illuminating the same sample with circularly polarised
light leads to a domain contrast with a different symmetry as the conventional
Kerr contrast. (iii) Circular polarisation can also be used for perpendicularly
magnetised material, demonstrated for a garnet film and an ultrathin CoFeB
film. (iv) Plane-polarised light at a specific angle can be employed for both,
in-plane and perpendicular media. (v) Perpendicular light incidence leads to a
domain contrast on in-plane materials that is quadratic in the magnetisation
and to a domain boundary contrast. (vi) Domain contrast can even be obtained
without polariser. In cases (ii) and (iii), the contrast is generated by MCD
(Magnetic Circular Dichroism), while MLD (Magnetic Linear Dichroism) is
responsible for the contrast in case (v). The domain boundary contrast is due
to the magneto-optical gradient effect in metallic samples. A domain boundary
contrast can also arise due to interference of phase-shifted magneto-optical
amplitudes. An explanation of these contrast phenomena is provided in terms of
Maxwell-Fresnel theory.
