Irfu-10-191 |
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Enhancing the spectral response of filled bolometer arrays for submillimeter astronomy |
V. Reveret, L. Rodriguez, P. Agnese |
The future missions for astrophysical studies in the submillimeter region will need detectors with very high sensitivity and large field of view. Bolometer arrays can fulfill these requirements over a very broad band. We describe a technique that enables bolometer arrays that use quarter wave cavities to have a high spectral response over most of the submillimeter band. This technique is based on the addition on the front of the array of an anti-reflecting dielectric layer. The optimum parameters (layer thickness and distance to the array) are determined by a 2D analytic code. This general principle is applied to the case of the Herschel PACS bolometers (optimized for the 60 - 210 micron band). As an example, we demonstrate experimentally that a PACS array covered by a 138 micron thick silicon layer can improve the spectral response by a factor 1.7 in the 450 micron band. |