Diffractive optical elements for optoelectronics

Abstract

Diffractive optical elements (DOEs) rely on the deflection of light waves by diffraction on microstructures rather than on refraction by smooth surfaces. They are well-suited for applications involving monochromatic light and lasers: They are flexible in design (synthetic holograms are designed by CAD), it is possible to fabricate array-optics (several elements precisely positioned side by side on one single substrate). DOEs may perform several functions at the same time (for example focusing, deflecting and beam splitting can be integrated into one component), they are often fabricated by planar technologies well known from microelectronics and they can be replicated, once one master has been made. Often DOEs are smaller and lighter in weight than conventional optical elements. Typical problems with DOEs are their wavelength dependence and the achievement of high diffraction efficiencies and low levels of straylight. Since DOEs usually have only very few optical surfaces (often just one) for diffractive lens systems the correction for aberrations, the field of view or tolerances against wavelength detuning are in many cases insufficient.