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19 November 2003 Liquid crystal intensity modulator for simulating planetary transits
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I describe a liquid crystal intensity modulator designed to achieve <10 parts per million (ppm) modulation to simulate a planetary transit like those required for ground testing of NASA's Kepler mission. The design uses a nematic liquid crystal as a variable retarder aligned between two linear polarizers, with the retardance values and the alignment chosen to provide low sensitivity of transmitted intensity to input liquid crystal voltage variations. Modulator test results give intensity fluctuations of a few ppm from millivolt modulations about the input 8 V baseline voltage.
© (2003) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Greg Kopp "Liquid crystal intensity modulator for simulating planetary transits", Proc. SPIE 5170, Techniques and Instrumentation for Detection of Exoplanets, (19 November 2003);

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