An optical element has a coating thereon to reflect energy, such as light, of a first polarization into a first focus zone and to allow energy, such as light, of a second polarization orthogonal to the first polarization, to reach a second optical element. The second optical element, which may be reflective,...http://www.google.com/patents/US6426838?utm_source=gb-gplus-sharePatent US6426838 - Polarization dependant multi-focus optical system
