Design and fabrication of continuous-profile diffractive micro-optical elements as a beam splitter

An optimization algorithm that combines a rigorous electromagnetic computation model with an effective iterative method is utilized to design diffractive micro-optical elements that exhibit fast convergence and better design quality. The design example is a two-dimensional 1-to-2 beam splitter that can symmetrically generate two focal lines separated by 80 mum at the observation plane with a small angle separation of +/-16degrees. Experimental results are presented for an element with continuous profiles fabricated into a monocrystalline silicon substrate that has a width of 160 mum and a focal length of 140 mum at a free-space wavelength of 10.6 mum. (C) 2004 Optical Society of America.