Conference paper
Hexabundles: imaging fibre arrays for low-light astronomical applications
We demonstrate for the first time an imaging fibre bundle (“hexabundle”) that is suitable for low-light applications in astronomy. The most successful survey instruments at optical-infrared wavelengths today have obtained data on up to a million celestial sources using hundreds of multimode fibres at a time fed to multiple spectrographs.
But a large fraction of these sources are spatially extended on the celestial sphere such that a hexabundle would be able to provide spectroscopic information at many distinct locations across the source. Our goal is to upgrade single-fibre survey instruments with multimode hexabundles in place of the multimode fibres.
We discuss two varieties of hexabundles: (i) closely packed circular cores allowing the covering fraction to approach the theoretical maximum of 91%; (ii) fused noncircular cores where the interstitial holes have been removed and the covering fraction approaches 100%. In both cases, we find that the cladding can be reduced to ~2μm over the short fuse length, well below the conventional ~10λ thickness employed more generally.
We discuss the relative merits of fused/unfused hexabundles in terms of manufacture and deployment, and present our first on-sky observations.
Language: | English |
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Year: | 2010 |
Pages: | 773541-12 |
Proceedings: | Ground-based and Airborne Instrumentation for Astronomy III |
ISSN: | 1996756x and 0277786x |
Types: | Conference paper |
DOI: | 10.1117/12.856345 |