Optically tunable guided-mode resonance filter

We have demonstrated a guided-mode resonance filter (GMRF) whose properties are tunable with laser illumination through the incorporation of a nonlinear dye. Laser illumination causes a change in the refractive index of the dye-doped portion of the structure, leading to controlled tuning of the GMRF reflectance spectrum. Changes in the refractive index of dye-doped regions are proportional to the intensity of the incident laser beam and are as high as Δn = 0.09. The reflectance tuning effect occurs on a time scale of many seconds and is completely reversible upon termination of the laser illumination.