AAS 204th Meeting, June 2004
Session 10 Instrumentation, Ground-based
Poster, Monday, May 31, 2004, 9:20am-6:30pm, Ballroom

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[10.08] LCDs as Slit Masks for Multi-Object Spectroscopy

B.A. Keeney, J.T. Stocke (CASA, Univ. of Colorado), D.-K. Yang (LCI, Kent St. Univ.)

We have examined the feasibility of using a liquid crystal device (LCD) as an electronically generated slit mask for multi-object spectroscopy. Bench tests were performed on a stack of two scattering principle LCDs that was found to have a clear-state transmission of 44 ±2% with a contrast ratio of 7.4 ±0.1 magnitudes. No attention has been paid to surface losses with the current device, but the clear-state transmission, and likely the contrast ratio, will increase with the application of an anti-reflection coating to the device's glass surfaces. The opacity of this device is achieved by scattering incident light out of the beam, but even a clear slit will scatter about 3% of a point source's light in the forward direction, creating a slightly non-uniform background. We find the results of these tests encouraging and plan to continue our feasibility study by performing on-telescope tests in the near future.

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