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The reformatting advantage: photonics vs conventional optics!

Calcines, Ariadna; Harris, Robert J.; Haynes, Roger; Haynes, Dionne

The reformatting advantage: photonics vs conventional optics! Thumbnail


Robert J. Harris

Roger Haynes

Dionne Haynes


Ramón Navarro

Roland Geyl


In recent decades, spectroscopic capabilities have been significantly enhanced by new technological developments, in particular spatial reformatting. Spatial reformatting allows multiple functionalities: the observation of a larger area of sky, obtaining the spectra of all spatial elements under the same atmospheric conditions; modification of the shape and size of the field of view; focal-ratio conversion for the optimized coupling between the telescope and the spectrograph; increase in the spatial and spectral resolving power; the observation of multiple objects; homogeneity in the illumination; scrambling of spatial and/or phase induced structure with the instrument, thus improving the system stability; relocation of the exit pupil, especially important for telecentric systems. The impact of reformatting and the breadth of science cases is so great that many alternative methods and technologies have been proposed: image slicers using refractive or reflective solutions; optical fibers with different core sizes and geometries; microlenses used in isolation or combined with fibers and more recently, photonic devices such as Photonic lanterns to produce modal decomposition. In this paper, a comparison between all currently available options is presented, with a detailed analysis of their advantages and limitations and a proposal for a new reformatter combining slicers and photonic devices. This proposal presents the advantages of the other alternatives and additionally offers: minimization of focal-ratio degradation; produces image and modal decomposition; improves the throughput along the spectral range, increases the spectral resolving power and adds the functionality of scrambling. All of these advantages are combined in a system where photonic and astronomical instrumentation capabilities are joined in an innovative solution with many applications, like for example, the Extremely Large Telescope.


Calcines, A., Harris, R. J., Haynes, R., & Haynes, D. (2018). The reformatting advantage: photonics vs conventional optics!. In R. Navarro, & R. Geyl (Eds.), Proceedings Volume 10706, Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation III.

Conference Name Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation III: SPIE Astronomical Telescopes + Instrumentation 2018
Conference Location Austin, Texas
Start Date Jun 10, 2018
End Date Jun 15, 2018
Online Publication Date Jul 10, 2018
Publication Date 2018
Deposit Date Sep 25, 2018
Publicly Available Date Jan 17, 2023
Publisher SPIE
Volume 10706
Book Title Proceedings Volume 10706, Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation III
ISBN 9781510619654
Public URL


Published Conference Proceeding (703 Kb)

Copyright Statement
Copyright (2018) Society of Photo Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.

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