Abstract: A broadband wire grid polarizer for the visible spectrum has a plurality of elongated elements supported on a substrate. A region having a lower refractive index than the refractive index of the substrate is disposed between the elements and the substrate to reduce the longest wavelength at which resonance occurs. The region may comprise a plurality of ribs extending from the substrate and supporting the elements. The ribs may be formed by etching slots into the substrate using the elements as a mask. The region may also comprise at least one layer of dielectric film. In addition the region may be comprise ribs extending from the surface, each having at least one layer of dielectric film disposed thereon.

Abstract: In an optical isolator including first and second birefringent plates whose optical axes are angularly different and a Faraday rotator inserted therebetween having a Faraday rotation angle of .theta..sub.f, (1) the angles of the optical axes of the first and second birefringent plates are so set that a forward incident polarized light passes through the first and second birefringent plates both as ordinary lights or both as extraordinary lights, and the relationship .theta..sub.f +.phi..sub.eff =90.degree. is satisfied when an actually used incident polarized light is incident in an oblique direction, or (2) the angles of the optical axes of the first and second birefringent plates are so set that a forward incident polarized light passes through one of the first and second birefringent plates as an ordinary light and the other birefringent plate as an extraordinary light, and the relationship .theta..sub.f -.phi..sub.eff =0.degree. is satisfied.