Chamber design for Fabry-Perot interferometer containment

Abstract

This paper outlines some of the "how-to" and "how-not-to" empirical experiences en countered in the design and construction of thermal/vacuum chambers for Fabry-Perot interferometer containment. The thermal environment is controlled to provide stable interferometric data for varying ambient temperatures. The interferometer operation in a vacuum ensures that the data will not vary with changes in the optical refractive index due to ambient pressure changes. Wedged windows are used to prevent secondary reflections from interfering with the data. Our paper reviews several examples of wedged-window attachments. Because a near-zero leak-proof design cannot be maintained with O-rings, small vacuum pumps are required to obtain continuous evacuation. We will also review our experiences relating to keeping chamber ambient temperature changes from affecting the interferometric data. We have used techniques providing a thermally stable interferometric system that produces stable data over an ambient-temperature range of 1540C with variations in ambient pressure.