Polarization converter

Abstract

A polarization converter P free from any particular limitation in the polarization direction of incident light or wavelength dependence, and large in the degree of freedom of selection of material is composed of polarization conversion unit P1, its united block, or combination or the like. P1 is composed of blocks of one body shape uniting three triangular columnar volume region elements having both ends in right-angled isosceles triangular form so that axial directions of triangular columns corresponding to the elements respectively may be directed in three mutually orthogonal directions. When a linear polarized light L enters vertically to surface 1a, its propagation route is in the sequence of incident point Q.fwdarw.total reflection point R1.fwdarw.total reflection point R2.fwdarw.total reflection point R3.fwdarw.exit point Q'. The incident ray L and exit ray L' are parallel to each other. The polarization direction is preserved at point R1, but is converted 90.degree. at R2, and preserved at R3 to be emitted out as L'. The polarization direction of L' is orthogonal to the polarization direction of L. Whichever the polarization direction of L may be, similar polarization conversion action is exhibited. Multiple polarization conversion units P1 or united blocks are optically and mechanically coupled with a thin substrate region made of optical material, and a polarization converter of sheet form is presented (Representative drawing) FIG. 1.