Enhancing daytime detection of objects with the use of a system incorporating dual diffractive elements with corresponding diffraction efficiencies and bandwidths

Abstract

An optical imaging system employing a device containing a sequence of first (pre-dispersor) and second (main) volume holograms configured to operate as a sequence of optical diffractive elements possessing different blazing curves. A pre-cursor hologram has a thickness smaller than the thickness of the following, disperser hologram, and a comparatively broad spectral selectivity as compared to that of the main hologram, allowing the pre-cursor to diffract light in transmission within a very large range of the angles of incidence. The use of the combination of the pre-cursor and the main holograms not only implements selective imaging of the chosen target object at every angle at which various portions of the object are seen at the optical system, but also facilitates the spectroscopic measurements of such object.