Patent ID: 9677935
Date: 2017-06-13
CPC Classifications: B82Y,G01J,G01N

Claim:
1. A system for wide-range spectral measurement, comprising: one or more broadband sources to illuminate a rugate tag, wherein the one or more broadband sources have a short broadband source coherence length, wherein light from the one or more broadband sources is reflected by a beam splitter toward a lens to illuminate the rugate tag, wherein the light illuminates the rugate tag at a first angular cone, wherein the lens to collect reflected light from the rugate tag at a second angular cone, wherein the second angular cone is greater than the first angular cone; an adjustable Fabry-Perot etalon to optically process the reflected light to extract spectral information with fine spectral resolution; a detector to detect reflected light from the rugate tag, wherein the reflected light is comprised of multiple narrow-band subsets of the illumination light having long coherence lengths and is optically processed using a plurality of settings for the adjustable Fabry-Perot etalon, and wherein the plurality of settings includes a separation of the Fabry-Perot etalon plates that is greater than the broadband source coherence length but that is less than the long coherence lengths; and a processor configured to determine if the detected reflected light from the rugate tag displays a predetermined reflectivity spectrum associated with the rugate tag.