Color Separation Echelon Gratings

Abstract

Color discrimination by wavelength bands has a large number of military and commercial applications. In the infrared portion of the spectrum, wavelength separation allows better temperature discrimination of thermally emissive objects. [1] In the visible portion of the spectrum, a device which separates white light into red, green, and blue wavebands without loss of energy could increase the efficiency of color sensors. An echelon-like grating structure [2,3] separates electromagnetic radiation of different wavelengths according to diffraction order rather than by dispersion within one diffraction order as would be the case for a conventional prism-type grating, as shown schematically in Figure 1.