Synthesis of polarization-selective optical components with multi-layer subwavelength structures

In this presentation we propose the multi-layer subwavelength structures to realize the polarization- sensitive optical elements. The multi-layer structures are fabricated on such consideration that a periodic relief subwavelength structure (we call the base structure later) with depth D-2 is first prepared in a substrate with refractive index n(1), then a dielectric material with a refractive index n(2) is directionally coated on it with thickness D-2.With the above fabrication process the coated dielectric material alternatively covers on the ridges or fills in the grooves of base structure to form the multilayer structures. The characteristics of the effective indices and the form-birefringence behaved in such structures were investigated. The form-birefringent wave plates and the blazed-binary polarization-selective diffractive optical elements for normal incidence were synthesized with the proposed structures. The optical behaviors included the phase retardation, diffraction efficiencies, and the polarization contrasts were numerically analyzed with rigorous electromagnetic algorithm. A quarter-wave plate for the operating wavelength of He-Ne laser ( lambda=632.8 nm) was fabricated and the significant optical performances was obtained.