Numerical optimization of diffractive optical elements for planar-integrated free-space optics

Planar-integrated free-space optics1,2 is a promising scheme to integrate large scale optical systems into a thick transparent substrate of plane-parallel geometry. For this approach all optical elements are located on the surfaces of the substrate (Fig. 1). Light signals propagate along a folded optical axis. All elements of the entire optical system form a two dimensional structure. This makes planar-integrated optics compatible with micro-electronics and allows, for instance, the fabrication of the system as a single diffractive optical surface relief by use of standard photo-lithographic techniques.