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Proceedings Paper

Rugate filters for OH-suppressed imaging
Author(s): Alison R. Offer; Jonathan Bland-Hawthorn
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Paper Abstract

Ground based observations beyond 0.68 microns are severely affected by intense and variable atmospheric OH bands that dominate the night sky spectrum. A number of OH suppression techniques have been proposed in the past using either dispersive or filter based techniques. Dispersive techniques are promising but potentially expensive and complex to implement. Filter based solutions have the advantage of being relatively cheap and easy to incorporate into existing instruments. However, the inflexibility of simple filter designs has made significant improvements in sensitivity difficult to achieve. Rugate filters are thin film filters with refractive indices that very continually through the coating. They enable the production of transmission profiles comprising a series of irregular and sharply defined band passes. In this paper we investigate the potential of rugate filters as OH suppression devices. We demonstrate through numerical simulation that it is possible to achieve almost complete suppression of the OH features in the J photometric band while retaining roughly half the spectral coverage. Such filters can potentially increase the signal to noise ratio for faint continuum sources by a factor of 2 in the J band and allow for considerably longer exposures before the detector saturates on the sky background.

Paper Details

Date Published: 9 July 1998
PDF: 9 pages
Proc. SPIE 3355, Optical Astronomical Instrumentation, (9 July 1998); doi: 10.1117/12.316821
Show Author Affiliations
Alison R. Offer, Anglo-Australian Telescope (Australia)
Jonathan Bland-Hawthorn, Anglo-Australian Observatory (Australia)


Published in SPIE Proceedings Vol. 3355:
Optical Astronomical Instrumentation
Sandro D'Odorico, Editor(s)

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