Stripe color separation with diffractive optics

Abstract

We describe a color separation optical element with potential display applications that is designed to separate light into an array of red, green, and blue stripes formed at a certain distance from the component. The stripe color separation grating is a surface-relief diffractive optical element composed of a repeated pattern of three constituent gratings. We describe the design principles and a numerical analysis of the component, showing that a maximum theoretical efficiency with which the colors are directed into the stripes is approximately 80%. We also examine the dependence of the efficiency on the grating feature size. In addition, we report on the fabrication of four of these components, using a combination of electron-beam lithography and photolithography with a backexposure technique. Measurements are presented to show the color separation property.