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First light demonstration of the integrated superconducting spectrometer

Nature Astronomy volume 3, pages 989–996 (2019)Cite this article

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Abstract

Ultra-wideband, three-dimensional (3D) imaging spectrometry in the millimeter–submillimeter (mm–submm) band is an essential tool for uncovering the dust-enshrouded portion of the cosmic history of star formation and galaxy evolution1,2,3. However, it is challenging to scale up conventional coherent heterodyne receivers4 or free-space diffraction techniques5 to sufficient bandwidths (≥1 octave) and numbers of spatial pixels2,3 (>102). Here, we present the design and astronomical spectra of an intrinsically scalable, integrated superconducting spectrometer6, which covers 332–377 GHz with a spectral resolution of F/ΔF ~ 380. It combines the multiplexing advantage of microwave kinetic inductance detectors (MKIDs)7 with planar superconducting filters for dispersing the signal in a single, small superconducting integrated circuit. We demonstrate the two key applications for an instrument of this type: as an efficient redshift machine and as a fast multi-line spectral mapper of extended areas. The line detection sensitivity is in excellent agreement with the instrument design and laboratory performance, reaching the atmospheric foreground photon noise limit on-sky. The design can be scaled to bandwidths in excess of an octave, spectral resolution up to a few thousand and frequencies up to ~1.1 THz. The miniature chip footprint of a few cm2 allows for compact multi-pixel spectral imagers, which would enable spectroscopic direct imaging and large-volume spectroscopic surveys that are several orders of magnitude faster than what is currently possible1,2,3.

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Fig. 1: ISS detection of redshifted CO(3–2) line emission from the LIRG VV 114.
Fig. 2: DESHIMA spectrometer system in the ASTE telescope cabin.
Fig. 3: DESHIMA spectral maps of the Orion nebula and the barred spiral galaxy NGC 253.
Fig. 4: Foreground photon-noise-limited sensitivity of the ISS and its fundamental limits.

Data availability

The datasets generated and analysed during this study are available from the corresponding author on reasonable request.

Code availability

The De:code software is distributed under the MIT license at https://github.com/deshima-dev/decode.

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Acknowledgements

We thank T. Kobiki, T. Ito, M. Yamada, M. Saito, J. Aguilera and J. Zenteno of NAOJ for their support at ASTE. We thank R. Jara, L. T. Galvéz and M. Konuma of NAOJ for their support in the transportation of the equipment to ASTE. We thank T. Minamidani for hosting a go/no-go review of the campaign, and all committee members who provided invaluable feedback. We thank K. Keizer of SRON for the precise mechanical work on the cryostat. We thank P. P. Kooijman and H. Hoevers of SRON for coordinating the delivery of the cryogenic hardware. We thank the staff of The University of Tokyo Atacama Observatory facility for their hospitality. We thank the staff of Kavli Nanolab Delft for their support in the microfabrication of the ISS chip. We thank the staff of Else Kooi Labratory for supporting the measurements in the cryolab at TU Delft. We thank D. Wernicke and J. Baumgartner of Entropy Cryogenics for their support in operating the cryostat at ASTE. Finally, we thank J. Pinto for his kindness to donate a piece of copper wire with a diameter in the range of 1.00–1.05 mm from his jewellery shop in San Pedro de Atacama so that we could align the cryogenic thermal mechanical structure on site. This research was supported by the Netherlands Organization for Scientific Research NWO (Vidi grant no. 639.042.423, NWO Medium Investment grant no. 614.061.611 DESHIMA), the European Research Council ERC (ERC-CoG-2014 - Proposal no. 648135 MOSAIC), the Japan Society for the Promotion of Science JSPS (KAKENHI grant nos. JP25247019 and JP17H06130), NAOJ ALMA Scientific Research grant no. 2018-09B, and the Grant for Joint Research Program of the Institute of Low Temperature Science, Hokkaido University. P.J.d.V. is supported by the NWO (Veni Grant 639.041.750). T.M.K. is supported by the ERC Advanced grant no. 339306 (METIQUM) and the Russian Science Foundation (grant no. 17-72-30036). N.L. is supported by ERC (Starting Grant no. 639749). J.S. and M.N. are supported by the JSPS Program for Advancing Strategic International Networks to Accelerate the Circulation of Talented Researchers (Program no. R2804). T.J.L.C.B. was supported by the European Union Seventh Framework Programme (FP7/2007–2013, FP7/2007–2011) under grant agreement no. 607254. The ASTE telescope is operated by the National Astronomical Observatory of Japan (NAOJ).

Author information

Authors and Affiliations

  1. Faculty of Electrical Engineering, Mathematics and Computer Science, Delft University of Technology, Delft, The Netherlands

    Akira Endo, Kenichi Karatsu, Sjoerd Bosma, Soh Ikarashi, Nuria Llombart, Alejandro Pascual Laguna, David J. Thoen, Ozan Yurduseven & Jochem J. A. Baselmans

  2. Kavli Institute of NanoScience, Faculty of Applied Sciences, Delft University of Technology, Delft, The Netherlands

    Akira Endo, Teun M. Klapwijk & David J. Thoen

  3. SRON—Netherlands Institute for Space Research, Utrecht, The Netherlands

    Kenichi Karatsu, Juan Bueno, Robert Huiting, Vignesh Murugesan, Alejandro Pascual Laguna, Pieter J. de Visser & Jochem J. A. Baselmans

  4. Division of Particle and Astrophysical Science, Graduate School of Science, Nagoya University, Nagoya, Japan

    Yoichi Tamura, Akio Taniguchi, Tom J. L. C. Bakx, Koyo Suzuki & Tetsutaro Ueda

  5. National Astronomical Observatory of Japan, Mitaka, Japan

    Tai Oshima, Shin’ichiro Asayama, Tom J. L. C. Bakx, Kah Wuy Chin, Yasunori Fujii, Shun Ishii, Ryohei Kawabe, Jun Maekawa, Kazushige Ohtawara & Takashi Tsukagoshi

  6. The Graduate University for Advanced Studies (SOKENDAI), Mitaka, Japan

    Tai Oshima & Ryohei Kawabe

  7. Institute of Astronomy, Graduate School of Science, The University of Tokyo, Mitaka, Japan

    Tatsuya Takekoshi, Tsuyoshi Ishida, Kotaro Kohno & Yuki Yoshimura

  8. Graduate School of Informatics and Engineering, The University of Electro-Communications, Chofu, Japan

    Tatsuya Takekoshi

  9. School of Physics & Astronomy, Cardiff University, Cardiff, UK

    Tom J. L. C. Bakx

  10. Department of Astronomy, School of Science, University of Tokyo, Tokyo, Japan

    Kah Wuy Chin & Ryohei Kawabe

  11. Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan

    Kazuyuki Fujita & Akira Kouchi

  12. Joint ALMA Observatory, Santiago, Chile

    Shun Ishii

  13. Physics Department, Moscow State Pedagogical University, Moscow, Russia

    Teun M. Klapwijk

  14. Research Center for the Early Universe, Graduate School of Science, The University of Tokyo, Tokyo, Japan

    Kotaro Kohno

  15. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Japan

    Shunichi Nakatsubo

  16. Graduate School of Science and Engineering, Saitama University, Saitama, Japan

    Masato Naruse

  17. High Energy Accelerator Research Organization (KEK), Tsukuba, Japan

    Junya Suzuki

  18. Leiden Observatory, Leiden University, Leiden, The Netherlands

    Paul P. van der Werf

  19. SRON—Netherlands Institute for Space Research, Groningen, The Netherlands

    Stephen J. C. Yates

Authors
  1. Akira Endo
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  2. Kenichi Karatsu
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  3. Yoichi Tamura
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  4. Tai Oshima
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  7. Shin’ichiro Asayama
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  8. Tom J. L. C. Bakx
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  13. Kazuyuki Fujita
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  19. Teun M. Klapwijk
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  27. Kazushige Ohtawara
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  29. Junya Suzuki
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  36. Stephen J. C. Yates
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  37. Yuki Yoshimura
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  38. Ozan Yurduseven
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  39. Jochem J. A. Baselmans
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Contributions

A.E. initiated the DESHIMA project as an MKID-based redshift machine. J.J.A.B. invented the concept of the ISS. P.P.v.d.W., Y.T., K. Kohno and R.K. articulated further astronomical usage of ISS spectrometers. A.E. designed the ISS filterbank. O.Y. designed the double-slot antenna. A.P.L. explained the chip performance with precise electromagnetic simulations. D.J.T. and V.M. fabricated the chip. D.J.T. and T.M.K. provided the NbTiN thin film. J.B. measured the optical efficiency of the chip. P.J.d.V. provided insight on the quasiparticle physics. S.J.C.Y. designed the cold optics, measured the instrument beam pattern, and did a post analysis to explain the beam pattern and efficiency measured on ASTE. J.J.A.B. and S.J.C.Y. made the conceptual design of the cryogenic set-up, and R.H. made the mechanical designs. J.J.A.B. developed the readout electronics. K. Karatsu measured the sensitivity and frequency response of the instrument. M.N. and J.S. contributed to these measurements. J.S. developed a database for managing the acquired data. S.B., O.Y. and N.L. designed the warm optics. T.O., T. Takekoshi, K.O. and Y.F. designed and tested the warm optics, the room-temperature calibration chopper and the DESHIMA–ASTE hardware interface. A.K. and K.F. manufactured the warm optics, and S.N. measured its surface accuracy. K. Karatsu, Y.T. and J.M. developed the DESHIMA local controller. D.J.T. and T.O. were responsible for the logistics in the transportation of the equipment to ASTE. T.O. led the installation of DESHIMA on ASTE, done by T.O., T. Takekoshi, K. Karatsu, D.J.T., R.H. and A.E. R.H. and K. Karatsu were responsible for the re-integration of the DESHIMA hardware on the ASTE site. K. Karatsu and T.O. realized remote control of DESHIMA on ASTE. T. Takekoshi aligned the warm optics using the scheme he developed. S. Ishii, A.T., Y.T., K. Karatsu, T. Takekoshi, T.U., T.I., K.C. and K.S. defined the data structure. A.T. and T.I. developed the De:code software. Y.T. led the astronomical observations and selected the target objects. Observations were conducted from the TAO facility in San Pedro de Atacama and from NAOJ by Y.T., K.S., T.I., A.T., T. Takekoshi, T.O., K. Karatsu, K.C., Y.Y., T.J.L.C.B., S. Ishii, T.U. and A.E. Y.T. developed the on-sky chopping scheme. T. Takekoshi led the dismounting of DESHIMA, done by T. Takekoshi, K. Karatsu, M.N., K.F. and A.E. The following authors autonomously analysed the on-telescope data and wrote the corresponding sections of this paper: K.S. (Mars), T. Takekoshi (sky dip calibration, in collaboration with J.S. and K. Karatsu), T. Tsukagoshi (VV 114, IRC+10216), S. Ikarashi (Orion, NGC 253). A.E. led the writing of the paper, and all authors have contributed to improving the quality. Project management: S.A. managed the ASTE telescope; J.J.A.B. managed the development of the instrument hardware; T.O. managed the development of the warm optics and chopper, as well as the scheme and hardware for installing DESHIMA on ASTE; Y.T. managed the astronomical commissioning and software development; A.E. managed the DESHIMA project on the top level.

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Correspondence to Akira Endo.

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Peer review information: Nature Astronomy thanks Ted Huang, Omid Noroozian and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Endo, A., Karatsu, K., Tamura, Y. et al. First light demonstration of the integrated superconducting spectrometer. Nat Astron 3, 989–996 (2019). https://doi.org/10.1038/s41550-019-0850-8

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