Patent ID: 6950173

Claim:
An inverse mode switchable grating system comprising: a holographically polymerized polymer dispersed liquid crystal material having a switchable grating formed therein; at least a first and a second electrode for applying a switching field to the switchable grating in order to vary a diffraction efficiency thereof, wherein application of the switching field increases the diffraction efficiency of the switchable grating and removal of the switching field decreases the diffraction efficiency of the switchable grating; a light signal having a p-polarization component and an s-polarization component; and wherein the grating is oriented such that an internal angle of p-polarized light incident thereon satisfies the following condition for a switching field of zero, tan ⁢ ⁢ θ ρ = ( ε xx ( 1 ) ε zz ( 1 ) ) 1 / 2 wherein θ p is the angle of incidence of a reference wave of the incident light and ∈ xx (1) and ∈ zz (1) are the x and z components of the modulation of a dielectric tensor for a material comprising the grating.