Spectroscopy using a visible photonic lantern at the Subaru Telescope: Laboratory characterization and the first on-sky demonstration on Ikiiki (
Year: 2024
Type: article
Abstract: Context. Photonic lanterns (PLs) are waveguide devices enabling high-throughput single-mode spectroscopy and high angular resolution. Aims. We aim to present the first on-sky demonstration of a PL operating in visible light, to measure its throughput and assess its potential for high-resolution spectroscopy of compact objects. Methods. We used the SCExAO instrument (a double-stage extreme adaptive optics system installed at the Subaru Telescope) and FIRST mid-resolution spectrograph (R 3000) to test the visible capabilities of the PL on internal source and on-sky observations. Results. The best averaged coupling efficiency over the PL field of view was measured at 51% ± 10%, with a peak at 80%. We also investigated the relationship between coupling efficiency and the Strehl ratio for a PL, comparing them with those of a single-mode fiber (SMF). Findings show that in the adaptive optics regime a PL offers a better coupling efficiency performance than an SMF, especially in the presence of low-spatial-frequency aberrations. We observed Ikiiki (α Leo – mR = 1.37) and ‘Aua (α Ori – mR = −1.17) at a frame rate of 200 Hz. Under median seeing conditions (about 1 arcsec measured in the H band) and large tip or tilt residuals (over 20 mas), we estimated an average light coupling efficiency of 14.5% ± 7.4%, with a maximum of 42.8% at 680 nm. We were able to reconstruct both star’s spectra, containing various absorption lines. Conclusions. The successful demonstration of this device opens new possibilities in terms of high-throughput single-mode fiber-fed spectroscopy in the visible. The demonstrated on-sky coupling efficiency performance would not have been achievable with a single SMF injection setup under similar conditions, partly because the residual tip or tilt alone exceeded the field of view of a visible SMF (18 mas at 700 nm). This emphasizes the enhanced resilience of PL technology to such atmospheric disturbances. The additional capabilities in high angular resolution are also promising but still have to be demonstrated in a forthcoming investigation.
Authors: S. Vievard, M. Lallement, S. Leon-Saval, O. Guyon, N. Jovanovic, E. Huby, S. Lacour, J. Lozi, V. Deo, K. Ahn, M. Lucas, S. Sallum, B. Norris, C. Betters, R. Amezcua-Correa, S. Yerolatsitis, M. P. Fitzgerald, J. Lin, Y. J. Kim, P. Gatkine, T. Kotani, M. Tamura, T. Currie, H-D. Kenchington, G. Martin, G. Perrin
Institutions: Astrobiology Center, National Astronomical Observatory of Japan, Centre National de la Recherche Scientifique, Université Paris Sciences et Lettres, Observatoire de Paris, Sorbonne Université, Sorbonne Paris Cité, Laboratoire d’études spatiales et d’instrumentation en astrophysique, The University of Sydney, California Institute of Technology, Korea Astronomy and Space Science Institute, University of Hawaii System, University of Hawaii at Hilo, University of California, Irvine, University of Central Florida, University of California, Los Angeles, The University of Texas at San Antonio, Institut de Planétologie et d'Astrophysique de Grenoble, Université Grenoble Alpes
Language: English
Subfield: Instrumentation
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: Development of Exoplanet Researches with New IR Technologies, Collaborative Research: Mastering the photonic lantern: The key to transformative diffraction-limited spectroscopy, Mapping Stellar Systems Birth and Death with NIR Polarized Imaging at AU scales., The formation of young giant exoplanets unveiled by optical interferometry, Direct imaging of exoplanets in the vicinity of the star with high contrast instruments, Measurements of relativistic effects from supermassive black hole using Subaru telescope and near-infrared wavefront sensor, Imaging habitable zone planets with Subaru Telescope and TMT, Integrated Optics for Optical Interferometry, G5266608198, Search for protoplanets with the FIRST instrument, Earth-like Planet Search on the Subaru Telescope, G8020484511, G8985346123
OpenAlex ID: W6903482354
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