Tilted bilayer membranes as simple transmission quarter-wave retardation plates

A tilted bilayer membrane, which consists of two thin films of transparent optically isotropic materials of different refractive indices, can function as a transmission quarter-wave retarder (QWR) at a high angle of incidence . A specific design using a cryolite-Si membrane in the infrared is present ed, and its tolerances to small shifts of wavelength, incidence angle, and film thickness errors are discussed. Some designs provide a dual QWR in tra nsmission and reflection. Such devices provide simple linear-to-circular la nd circular-to-linear) polarization transformers. Bilayer eighth-wave retar ders without diattenuation are also introduced. (C) 2001 Optical Society of America OCIS codes: 120.2130, 230.0230, 240.0310, 260.5430.