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Proceedings Paper

Scattered light in a DMD based multi-object spectrometer
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Paper Abstract

The DMD (Digital Micromirror Device) has an important future in both ground and space based multi-object spectrometers. A series of laboratory measurements have been performed to determine the scattered light properties of a DMD. The DMD under test had a 17 μm pitch and 1 μm gap between adjacent mirrors. Prior characterization of this device has focused on its use in DLP (TI Digital Light Processing) projector applications in which a whole pixel is illuminated by a uniform collimated source. The purpose of performing these measurements is to determine the limiting signal to noise ratio when utilizing the DMD as a slit mask in a spectrometer. The DMD pixel was determined to scatter more around the pixel edge and central via, indicating the importance of matching the telescope point spread function to the DMD. Also, the generation of DMD tested here was determined to have a significant mirror curvature. A maximum contrast ratio was determined at several wavelengths. Further measurements are underway on a newer generation DMD device, which has a smaller mirror pitch and likely different scatter characteristics. A previously constructed instrument, RITMOS (RIT Multi-Object Spectrometer) will be used to validate these scatter models and signal to noise ratio predications through imaging a star field.

Paper Details

Date Published: 20 July 2010
PDF: 9 pages
Proc. SPIE 7739, Modern Technologies in Space- and Ground-based Telescopes and Instrumentation, 77393X (20 July 2010); doi: 10.1117/12.869549
Show Author Affiliations
Kenneth D. Fourspring, Rochester Institute of Technology (United States)
Zoran Ninkov, Rochester Institute of Technology (United States)
John P. Kerekes, Rochester Institute of Technology (United States)

Published in SPIE Proceedings Vol. 7739:
Modern Technologies in Space- and Ground-based Telescopes and Instrumentation
Eli Atad-Ettedgui; Dietrich Lemke, Editor(s)

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