Fabrication of micro-optics and diffractive lenses using analogue methods

The most important aspect of producing a diffracting optical component that will compare well with its refracting or reflecting counterpart is to achieve an adequate level of diffraction efficiency. Binary diffracting structures in amplitude and phase forms have been available for about a century but since their efficiency is limited to 10% and 40% respectively they have not found significant application. In order to achieve high efficiency it is necessary to exercise some control over the form of the grooves and for most practical cases it is necessary to generate a saw-tooth “blazed” profile. A blazed profile is one in which the individual facets behave, to a first approximation, like tiny prisms which send the light by reflection or refraction in the same direction that the spacing of the grooves sends it by diffraction.