Parallelism of a Fabry-Perot cavity at micron spacings

D. Heath Jones, Joss Bland-Hawthorn

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)

Abstract

We describe a method to quantify the degree of parallelism between two transparent glass mirrors spaced a few microns apart. Our technique, which permits the measurement and correction of deviations as small as λ/10000 from parallelism, is fundamental to the successful operation of tunable narrowband interference filters for two reasons. First, the highest throughput is achieved when the plates are parallel at any plate spacing. Second, the lowest resolution (largest bandpass) imaging is achieved when the plates are only a few microns apart, but there is a real danger of the plates touching if parallelism is not maintained. The Taurus Tunable Filter (TTF)3 is a Fabry-Perot cavity with an adjustable plate spacing of 2-13 μm. The parallelism measurement involves repeated imaging through a local-plane slit and a series of pupil-plane masks. This approach is particularly efficient when the plate scanning is synchronized with the movement of the charge on the CCD. We assess the effects of wavelength-dependent phase changes within the inner surface coatings of the plates. These become important as the plates approach a spacing comparable in size to the thickness of the coatings.

Original languageEnglish
Pages (from-to)1059-1066
Number of pages8
JournalPublications of the Astronomical Society of the Pacific
Volume110
Issue number751
DOIs
Publication statusPublished - Sep 1998

Fingerprint

Dive into the research topics of 'Parallelism of a Fabry-Perot cavity at micron spacings'. Together they form a unique fingerprint.

Cite this