title: Dichroic rugate filters based on birefringent porous silicon.
abstract: Rugate filters made of anisotropically nanostructured birefringent silicon have been fabricated and studied by polarization-resolved transmission measurements. Electrochemical etching of a (110) oriented Si wafer results in porous silicon layers which exhibit a strong in-plane birefringence. We demonstrate that a sinusoidal refractive index variation of birefringent porous silicon combined with index-matching layers and apodization results in a dichroic rugate filter having a stop-band dependent on the polarization direction of the incident light without higher-order harmonics and sidelobes. We also demonstrate that the combination of different dichroic rugate filters allow us to realize filters with more complex properties in a single preparation step.
authors.affiliation: Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University, Rokkodai, Nada, Kobe 657-8501, Japan.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Ishikura
authors.forename: Minoru
authors.initials: M
authors.lastname: Fujii
authors.forename: Kohei
authors.initials: K
authors.lastname: Nishida
authors.forename: Shinji
authors.initials: S
authors.lastname: Hayashi
authors.forename: Joachim
authors.initials: J
authors.lastname: Diener
mesh_terms: D016880:Anisotropy; D003201:Computers; D004563:Electrochemistry / Q000379:methods; D004867:Equipment Design; D005374:Filtration / Q000295:instrumentation; D008027:Light; D046529:Microscopy, Electron, Transmission; D015233:Models, Statistical; D055095:Optics and Photonics; D012825:Silicon / Q000737:chemistry
chemical_list: D012825:Silicon