21 July 2010 Custom beamsplitter and AR coatings for interferometry
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We report on final fabrication tests for the dielectric coatings for the Magdalena Ridge Observatory Interferometer (MROI) fringe tracking beam combiner. The broadband anti-reflection (1.1 μm to 2.4 μm) and beamsplitter (1.49 μm to 2.31 μm) coatings required have been designed with both optical and mechanical constraints in mind. Not only do these coatings have very low optical losses, but they induce minimal bending of their substrates, thereby giving very low fringe contrast reductions. Performance tests on the deposited coatings at our manufacturers (Optical Surface Technologies, Albuquerque, NM) demonstrate reflection losses of less than 0.5% over the full bandpass of the AR coating, and deviations from the desired 50:50 intensity ratio of the beamsplitter coating of no more than 2%. When combined with the measured wavefront perturbations these results imply that the total fringe visibility losses induced by imperfect coating quality will be no more than 2% for all outputs of the MROI fringe tracking beam combiner.
© (2010) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
K. Nyland, K. Nyland, C. A. Jurgenson, C. A. Jurgenson, D. F. Buscher, D. F. Buscher, C. A. Haniff, C. A. Haniff, J. S. Young, J. S. Young, J. Lewis, J. Lewis, R. Schnell, R. Schnell, } "Custom beamsplitter and AR coatings for interferometry", Proc. SPIE 7734, Optical and Infrared Interferometry II, 77343U (21 July 2010); doi: 10.1117/12.857162; https://doi.org/10.1117/12.857162


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