title: High efficiency half-wave retardation in diffracted light by coupled waves.
abstract: We demonstrate high-efficiency half-wave retardation in diffracted light in the 2nd order Littrow mounting. The diffracting structure is a slanted crossed grating with subwavelength period in the direction of the second grating vector, which makes it possible to mix the polarization states of the input light inside the grating layer, and hence to create the half-wave retardation. We present an experimental result with 58.9 % diffraction efficiency and a near perfect half-wave retardation. We explain the effect qualitatively using the classical coupled-wave approach.
authors.affiliation: Department of Physics and Mathematics, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland. kalle.ventola@uef.fi
authors.forename: Kalle
authors.initials: K
authors.lastname: Ventola
authors.forename: Jani
authors.initials: J
authors.lastname: Tervo
authors.forename: Samuli
authors.initials: S
authors.lastname: Siitonen
authors.forename: Hemmo
authors.initials: H
authors.lastname: Tuovinen
authors.forename: Markku
authors.initials: M
authors.lastname: Kuittinen