Wideband circular polarization reflector fabricated by glancing angle deposition

We demonstrate a wideband circular polarization reflector fabricated as cascades of helical films with different pitch thickness by using glancing angle deposition (GLAD) technique. The full-width-at-half-maximum bandwidth of this reflector is measured from the reflectance spectra and is found about 200 nm indicating the feasibility of wideband reflector. A helical TiO2 film with three sections, each of different pitch thickness, is also studied. It shows three Bragg peaks at different wavelengths. To select appropriate material for this circular reflector, the optical properties of 5-turns TiO2, ZrO2, and Ta2O5 helical films and the porosity effect on the TiO2 helical film are investigated. (C) 2008 Optical Society of America.