Efficient photonic reformatting of celestial light for diffraction-limited spectroscopy

David Guillaume MacLachlan, Robert J. Harris, I. Gris-Sanchez, T. J. Morris, Debaditya Choudhury, Eric Gendron, Alastair Basden, Izabela Spaleniak, Alexander Arriola, Timothy A. Birks, Jeremy R. Allington-Smith, Robert R. Thomson

Research output: Contribution to journalArticle

41 Downloads (Pure)

Abstract

The spectral resolution of a dispersive astronomical spectrograph is limited by the trade-off between throughput and the width of the entrance slit. Photonic guided-wave transitions have been proposed as a route to bypass this trade-off, by enabling the efficient reformatting of incoherent seeing-limited light collected by the telescope into a linear array of single modes: a pseudo-slit which is highly multimode in one axis but diffraction-limited in the dispersion
axis of the spectrograph. It is anticipated that the size of a single-object spectrograph fed with light in this manner would be essentially independent of the telescope aperture size. A further anticipated benefit is that such spectrographs would be free of ‘modal noise’, a phenomenon that occurs in high-resolution multimode fibre-fed spectrographs due to the coherent nature
of the telescope point-spread-function (PSF). We seek to address these aspects by integrating a multicore fibre photonic lantern with an ultrafast laser inscribed three-dimensional waveguide interconnect to spatially reformat the modes within the PSF into a diffraction-limited pseudo-slit. Using the CANARY adaptive optics (AO) demonstrator on the William Herschel Telescope, and 1530 80 nm stellar light, the device exhibits a transmission of 47 – 53 per cent depending upon the mode of AO correction applied.We also show the advantage of using AO to couple light into such a device by sampling only the core of the CANARY PSF. This result underscores the possibility that a fully-optimised guided-wave device can be used with AO to provide efficient spectroscopy at high spectral resolution.
Original languageEnglish
Pages (from-to)4950-4957
Number of pages8
JournalMonthly Notices of the Royal Astronomical Society
Volume464
Issue number4
Early online date6 Oct 2016
DOIs
Publication statusPublished - 1 Feb 2017

Keywords

  • instrumentation: adaptive optics
  • instrumentation: spectrographs

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Fingerprint Dive into the research topics of 'Efficient photonic reformatting of celestial light for diffraction-limited spectroscopy'. Together they form a unique fingerprint.

  • Cite this

    MacLachlan, D. G., Harris, R. J., Gris-Sanchez, I., Morris, T. J., Choudhury, D., Gendron, E., Basden, A., Spaleniak, I., Arriola, A., Birks, T. A., Allington-Smith, J. R., & Thomson, R. R. (2017). Efficient photonic reformatting of celestial light for diffraction-limited spectroscopy. Monthly Notices of the Royal Astronomical Society, 464(4), 4950-4957. https://doi.org/10.1093/mnras/stw2558