WIDE SPECTRAL BAND SUB-WAVELENGTH DIFFRACTIVE COMPONENT

摘要

The invention relates to a diffractive component (10) capable of broadband diffract an incident beam having a wavelength in a spectral band of diffraction, -the diffractive component comprising a plurality of unit areas arranged on a surface (S), each elementary zone belonging to a type indexed by an index i from 1 to n with n strictly greater than 1, the index i corresponding to a length wave blaze .lambda.i of index i, the blaze wavelength being included in the spectral band of diffraction, -a i-type elementary zone (Zi, Z'i, Z "i) comprising a plurality of microstructures (MSi) having respectively at least one size (di) less than 1.5 times the wavelength of blaze (.lambda.i ) of index i, the microstructures are arranged to form an artificial material with variation of effective index (n _eff (i)) so that an i-type elementary area is a blazed diffractive element to the length of blaze .lambda.i of index i, -the different values ​​of the blaze wavelengths and the occupied area ratio by all the areas of a given type depending on a desired overall diffraction efficiency in the diffraction spectral band.