Patent ID: 7570405

Claim:
A method for switching a holographic diffraction grating via a switching field between a first diffraction efficiency and a second diffraction efficiency comprising: orienting the holographic diffraction grating such that an internal angle of p-polarized light incident thereon satisfies the following condition for a switching field of zero, tan ⁢ ⁢ θ ρ = ( ɛ x ⁢ ⁢ x ( 1 ) ɛ z ⁢ ⁢ z ( 1 ) ) 1 / 2 wherein θ ρ is the angle of incidence of a reference wave of the incident light and ε xx (1) and ε zz (1) are the x and z components of the modulation of the dielectric tensor for a material comprising the holographic diffraction grating and the holographic diffraction grating has a first diffraction efficiency; and applying a switching field greater than zero in order to switch the holographic diffraction grating to a second diffraction efficiency.