Athermal channeled spectropolarimeter
| DWPI Title: Athermal channeled spectropolarimeter used in remote sensing application, has retarder and polarizer that are optically positioned in series, such that transmission axis of electromagnetic signal passes through retarder and polarizer |
| Abstract: A temperature insensitive (athermal) channeled spectropolarimeter (CSP) is described. The athermal CSP includes a crystal retarder formed of a biaxial crystal. The crystal retarder has three crystal axes, wherein each axis has its own distinct index of refraction. The axes are oriented in a particular manner, causing an amplitude modulating carrier frequency induced by the crystal retarder to be thermally invariant. Accordingly, a calibration beam technique can be used over a relatively wide range of ambient temperatures, with a common calibration data set. |
| Use: Athermal channeled spectropolarimeter (CSP) such as point source athermal CSP used in remote sensing application, for analyzing visible and near infrared spectrum. |
| Advantage: The crystal retarder in CSP is provided with relatively precise orientation, in order to obtain accurate measurement for the frequency spectrum of the EM signal that is subjected to analysis. The calibration data is taken frequently or precise thermal stability of the system is maintained actively, so as to avoid calibration errors. |
| Novelty: The channeled spectropolarimeter (300) has a crystal retarder (102) which is formed of a biaxial crystal. A spectrometer (106) such as dispersive spectrometer is in optical communication with a polarizer (104). The crystal retarder and the polarizer are optically positioned in series, such that a transmission axis of an electromagnetic (EM) signal is passed through the crystal retarder and the polarizer. The crystal retarder is formed of potassium titanyl phosphate. |
| Filed: 2/27/2014 |
| Application Number: US14192543A |
| Tech ID: SD 12560.1 |
| This invention was made with Government support under Contract No. DE-NA0003525 awarded by the United States Department of Energy/National Nuclear Security Administration. The Government has certain rights in the invention. |
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