Polarization-selective computer-generated holograms: design, fabrication, and applications

Abstract

We constructed polarization-selective computer-generated holograms that apply an independent phase profile during readout by horizontal and vertical light polarizations. These elements are composed of two surface-relief-etched birefringent substrates joined face to face. We describe the design methodology for arbitrary birefringent substrate and gap materials. We show how these holograms are fabricated with standard microelectronics technology and discuss the effects of etching and alignment errors on performance. We demonstrated a diffraction efficiency of 60% with a polarization contrast ratio of >100:1 using a multilevel phase hologram made from two birefringent lithium niobate substrates. We also showed that a single-layer SiO(2) thin-film antireflection coating on all surfaces can reduce reflections from the high-index substrates without significant effect on hologram performance. We also consider some possible applications of this technology and demonstrate experimentally a dual focal-length lens and a self-interconnecting binary 2 × 2 polarization switch.

Fabrication, modeling, and characterization of form-birefringent nanostructures

“…BCGH elements are useful in various applications. 8 In its original design 9 a BCGH consists of two surface-relief substrates with at least one of them birefringent. The two independent etch depths of the BCGH element provide the two degrees of freedom necessary to encode the two independent phase functions.…”

“…3 (iii) FBN's can be used to modify the ref lection properties of the dielectric boundaries. 3,5 Such FBN's are useful for constructing polarization-selective beam splitters 6,7 and generalpurpose polarization-selective diffractive optical elements such as birefringent computer-generated holograms 8 (BCGH's). A BCGH is a general-purpose diffractive optical element that has two independent though arbitrary impulse responses for the two orthogonal linear polarizations.…”

Design of diffractive elements at millimeter wavelengths using subwavelength cylindrical microstructures

“…Waveguide filters have been extensively used in microwave and millimeter wave engineering for many years [1][2][3]. Because of their high power-handling and high reliability, they were usually applied in deep-space and military radar applications.…”

Jones matrix treatment for polarization Fourier optics

“…These kind of element can be fabricated either using subwavelength structures [1][2][3] or employing liquid-crystal displays [4,5], this latter having the advantage of being reprogrammable elements. The study of the diffracted field generated by these kinds of spatially variant polarization element has attracted considerable effort.…”