Multifractal interference mirrors having fractal dimensions between 0 and 1

摘要

The invention relates to a self-similar multilayer mirror enabling radiation of different wavelengths to be reflected selectively and simultaneously. The stacked arrangement is multifractal. It consists of a stacked arrangement of thin layers which is constructed according to the generalised Cantor set. It is constructed in the following iterative manner: let Gj be the multilayer obtained at step j, and its thickness is hj. The multilayer Gj+1 is obtained by adding to G, the replica (repeat) Gj translated by the distance (mj+1-1) hj in the direction of the lamination (stratification) in such a way that the thickness of the multilayer Gj+1 is hj+1 = mj+1 hj. A material of optical index nj+1 (j = 1,2,...N) is deposited into the empty space between the translated replica (Gj) and the non-translated multilayer Gj. The device therefore consists of a backing (support) (1), of the seed (2) which is a stacked arrangement of layers, of the first spacer medium (3), of the 2nd spacer medium (5) and so on. At step zero, there is a seed (2), at step one, there are two seed (4) and at step j there are 2j seed. The stacked arrangement is made using vacuum evaporation techniques. The multilayer according to the invention is particularly intended to reflect, completely and selectively, a discontinuous and/or continuous electromagnetic-radiation and neutron-radiation spectrum. IMAGE