  The conventional linear polarizer only allows the electric component parallel
to the polarizer axis to pass through whereas prohibits the vertical component.
We propose that a specially-designed single-layer plasmonic polarizer can
couple both parallel and vertical electric components to the transmission, thus
breaking the classical law of Malus. A variety of anomalous polarization
effects, such as the asymmetric polarization-angle dependence, enhanced
polarization filtering with wide polarization angle, and tunable polarization
rotation from 0o to 90o, can be resulted. To understand the effects, the
generalized law of Malus,originating from the superposition principle, has been
presented and analyzed. This provides a basis for studying the
interference-type plasmonic polarizers, where the interference effect and
polarization effect are combined together. The difference between the plasmonic
and conventional polarizers is of both fundamental and practical interests.
