First stellar photons for an integrated optics discrete beam combiner at the William Herschel Telescope

Nayak, Abani Shankar; Labadie, Lucas; Sharma, Tarun Kumar; Piacentini, Simone; Corrielli, Giacomo; Osellame, Roberto; Gendron, Éric; Buey, Jean-Tristan M.; Chemla, Fanny; Cohen, Mathieu; Bharmal, Nazim A.; Bardou, Lisa F.; Staykov, Lazar; Osborn, James; Morris, Timothy J.; Pedretti, Ettore; Dinkelaker, Aline N.; Madhav, Kalaga V.; Roth, Martin M.

Abstract

We present the first on-sky results of a four-telescope integrated optics discrete beam combiner (DBC) tested at the 4.2 m William Herschel Telescope. The device consists of a four-input pupil remapper followed by a DBC and a 23-output reformatter. The whole device was written monolithically in a single alumino-borosilicate substrate using ultrafast laser inscription. The device was operated at astronomical H-band (1.6 µm), and a deformable mirror along with a microlens array was used to inject stellar photons into the device. We report the measured visibility amplitudes and closure phases obtained on Vega and Altair that are retrieved using the calibrated transfer matrix of the device. While the coherence function can be reconstructed, the on-sky results show significant dispersion from the expected values. Based on the analysis of comparable simulations, we find that such dispersion is largely caused by the limited signal-to-noise ratio of our observations. This constitutes a first step toward an improved validation of the DBC as a possible beam combination scheme for long-baseline interferometry.

Citation

Nayak, A. S., Labadie, L., Sharma, T. K., Piacentini, S., Corrielli, G., Osellame, R., …Roth, M. M. (2021). First stellar photons for an integrated optics discrete beam combiner at the William Herschel Telescope. Applied Optics, 60(19), D129-D142. https://doi.org/10.1364/ao.423881

• Journal Article Type: Article
• Acceptance Date: Jun 13, 2021
• Online Publication Date: Jun 14, 2021
• Publication Date: 2021-07
• Deposit Date: Jul 19, 2021
• Publicly Available Date: Jan 20, 2022
• Journal: Applied Optics
• Print ISSN: 1559-128X
• Electronic ISSN: 2155-3165
• Publisher: Optica
• Peer Reviewed: Peer Reviewed
• Volume: 60
• Issue: 19
• Article Number: D129
• Pages: D129-D142
• DOI: https://doi.org/10.1364/ao.423881
• Public URL: https://durham-repository.worktribe.com/output/1271863