High performance bi-dimensional resonant grating filter at 850nm under high oblique incidence of ∼60°

We present an experimental demonstration of a polarization quasi-independent narrow-band (less than 0.8nm) filter operating under high oblique incidence. The structure is a resonant grating with a hexagonal lattice which has been carefully designed to ensure polarization quasi-independence of the narrow-band resonance peak over a wide angular range around 60° of incidence. A good agreement between experimental results and theoretical calculations is shown.