Optical device augmenting the emission of electro-luminescent light sources with help of a dichroic ZnO nanorod comprising filter

An optical device to be applied to electro-luminescent lamps that include, at least, fluorescent lamps and white light emitting diodes (LED), the optical device configured to be external to a source for generating light comprising:

• an optical reflector;
• and
• a multilayer optical filter, wherein
• the optical reflector includes a specular or diffuse metallic surface, having a reflectance of not less than 98%, the specular or diffuse metallic surface is configured to reflect the light generated by the source towards a work plane;
• the multilayer optical filter includes a transparent and rigid multilayer structure having a transparent organic or inorganic material that serves as a substrate on which a layer of zinc oxide is applied, the layer of zinc oxide being an active layer of the multilayer optical filter, the layer of zinc oxide having a thickness of 1.5 to 3 micrometers, and containing, in an interior of the layer of zinc oxide, a nanostructure of zinc oxide nano wires having a lattice constant from 200 nm to 400 nm, a filling ratio from 0.5 to 0.8, and a height from 1 to 2 micrometers, said multilayer optical filter configured to behave as a partial light reflector in a bandwidth range of 380 nm to 530 nm and further configured to behave as an antireflective element in the bandwidth range of 531 nm to 1100 nm;
• and
• the refractive indexes of the substrate and the zinc oxide layer of the multilayer optical filter are displaced in phase 180°.