摘要 |
A Zero-order diffractive filter comprising a first layer (1) with a periodic diffractive microstructure, forming a waveguide, and at least one adjacent second layer (2, 4, 5), wherein said first layer (1) has a refractive index that is higher than the refractive index of said second layer (2, 4, 5) by at least 0.2. At least one of said second layers (2, 4, 5) is a porous layer comprising nanopores. The period Λ of the diffractive microstructure is between 100 nm and 3000 nm.
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