Design study for a multilevel dispersive microlens

Abstract

A micro-optical element that is a combination of a phase diffraction grating and a convex lens will disperse and focus light of different wavelengths that fall on it. Such a device can be fabricated using binary optics technology to create a multilevel structure that approximates the element. The performance of this multilevel dispersive microlens depends on design parameters such as the grating period and the f-number of the lens. The performance also depends on the resolution used in the fabrication of the element (feature sizes and etching depths). We present a study of how these design parameters and resolution requirements affect performance characteristics of the element, such as diffraction efficiencies, blur spot sizes, and wavelength dispersion.