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Three-dimensional micro-Fresnel optical elements fabricated by micromachining technique

We report, for the first time, a three-dimensional binary phase micro-Fresnel optical element standing perpendicular to the substrate. The lens is fabricated by micromachining technique. The lens has a diameter of 650 µm, a focal length of 0.5 mm, and an optical axis of 1 mm above the surface of the substrate. Light from an optical fibre is successfully collimated by the micro-optical element, and the beam profile closely approximates a Gaussian shape.