Switching of optical properties in zeolitic nanocomposites

Abstract

The guest molecule azobenzene is aligned nearly perfectly by the channels of the molecular sieve AlPO₄-5. After irradiation with light of the wavelength 360 nm the configuration and the orientation of the molecules are changed. This results in changes of the refractive index. It turns out that this reaction is reversible (back reaction by irradiation with 436 nm) and that the change of the birefringence can be very large (δn' = 0,033). It is demonstrated that a crystal of a thickness of 13 μm is sufficient to be switched between a λ-plate and a λ/2-plate. This is an example of an opto-optical microswitch.