Recording a reversible photoinduced birefringence in a lightguide

Abstract
Planar waveguides of the azo dye methyl-red in poly(methyl methacrylate) were spin coated on quartz glass. The transmission of simultaneously launched TE and TM modes (wavelength of the guided light: λ=633 nm) is studied under exposure to blue laser light (λ=488 nm). The guided light may be modulated by the exposing light at low speeds.