Patent ID: 7854505

Claim:
An optical device for protecting an eye or sensor from incident electromagnetic radiation generated by a laser; said device comprising; a first photonic crystal having a spatial distribution of refractive indices that varies periodically in at least two dimensions and positioned to intersect said electromagnetic radiation generated by a laser, said first photonic crystal comprising a dielectric structure comprising alternating high refractive index elements and low refractive index elements provided in a periodic spatial configuration in at least two dimensions, and said photonic crystal having a photonic band gap, wherein said incident electromagnetic radiation generated by said laser has a first range of frequencies, wherein the spatial distribution of refractive indices of said first photonic crystal and the refractive indices of said high and low refractive index elements are selected such that the photonic band gap of said first photonic crystal at least partially overlaps said first range of frequencies of said incident electromagnetic radiation generated by said laser; and wherein said first photonic crystal is a component of said optical device positioned to prevent transmission of substantially all of said incident electromagnetic radiation generated by said laser through said device to said eye or said sensor.