A cooled optically servo-controlled infrared Fabry-Perot spectrometer has been constructed. The control system maintains both alignment and spacing of a tunable infrared etalon. An annular portion of the IR etalon is coated for control use at visible wavelengths. Correct spacing is determined by reference to an associated visible etalon of fixed and slightly different spacing. The spacing of the IR etalon then varies approximately linearly with the output wavelength of a visible control monochromator. The full range of the mono-chromator, typically 500 to 700 nm, corresponds to a change in etalon spacing which can be as little as a small fraction of an IR order or as much as several orders. The movable plate of the IR etalon is positioned by an electromagnetic drive system with a mechanical range of about a millimeter. The instrument is planned to accommodate up to three IR etalons which can be scanned synchronously by tuning the output of a single control mono-chromator. A single-etalon version of the spectrometer has been operated at the Cassegrain focus of the KPNO 1.3m telescope.

Date Published: 9 January 1984
PDF: 11 pages
Proc. SPIE 0445, Instrumentation in Astronomy V, (9 January 1984); doi: 10.1117/12.966118

Published in SPIE Proceedings Vol. 0445:
Instrumentation in Astronomy V
Alec Boksenberg; David L. Crawford, Editor(s)