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Simulating the study of exoplanets using photonic spectrographs

Perez, Marcos and Gatkine, Pradip and Jovanovic, Nemanja and Jewell, Jeffrey and Wallace, J. Kent and Mawet, Dimitri (2022) Simulating the study of exoplanets using photonic spectrographs. In: Photonic Instrumentation Engineering IX. Proceedings of SPIE. No.12008. Society of Photo-optical Instrumentation Engineers , Bellingham, WA, Art. No. 120080C.

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Photonic spectrographs offer a highly miniaturized, flexible, and stable on-chip solution for astronomical spectroscopy and can be used for various science cases such as determining the atmospheric composition of exoplanets to understand their habitability, formation, and evolution. Arrayed Waveguide Gratings (AWGs) have shown the best promise to be used as an astrophotonic spectrograph. We developed a publicly-available tool to conduct a preliminary examination of the capability of the AWGs in spectrally resolving exoplanet atmospheres. We derived the Line-Spread- Function (LSF) as a function of wavelength and the Full-Width-at-Half-Maximum (FWHM) of the LSF as a function of spectral line width to evaluate the response of a discretely- and continuously sampled low-resolution AWG (R ~ 1000). We observed that the LSF has minimal wavelength dependence (~5%), irrespective of the offset with respect to the center-wavelengths of the AWG channels, contrary to the previous assumptions. We further confirmed that the observed FWHM scales linearly with the emission line width. Finally, we present simulated extraction of a sample molecular absorption spectrum with the discretely- and continuously-sampled low-resolution AWGs. From this, we show that while the discrete AWG matches its expected resolving power, the continuous AWG spectrograph can, in principle, achieve an effective resolution significantly greater (~ 2x) than the discrete AWG. This detailed examination of the AWGs will be foundational for future deployment of AWG spectrographs for astronomical science cases such as exoplanet atmospheres.

Item Type:Book Section
Related URLs:
URLURL TypeDescription Paper
Gatkine, Pradip0000-0002-1955-2230
Jovanovic, Nemanja0000-0001-5213-6207
Wallace, J. Kent0000-0001-5299-6899
Mawet, Dimitri0000-0002-8895-4735
Additional Information:© 2022 Society of Photo-Optical Instrumentation Engineers (SPIE). M. Perez acknowledges the support from Caltech Summer Undergraduate Research Fellowship (SURF) program and the funding provided by the Flintridge Foundation for his work in the summer of 2021. P. Gatkine was supported by NASA Hubble Fellowship program as well as David & Ellen Lee Fellowship at Caltech. This work was supported by the Wilf Family Discovery Fund in Space and Planetary Science, funded by the Wilf Family Foundation. This research was carried out at the California Institute of Technology and the Jet Propulsion Laboratory under a contract with the National Aeronautics and Space Administration (NASA) and funded through the President’s and Director’s Research & Development Fund Program.
Group:Astronomy Department
Funding AgencyGrant Number
Caltech Summer Undergraduate Research Fellowship (SURF)UNSPECIFIED
Flintridge FoundationUNSPECIFIED
David and Ellen Lee Postdoctoral ScholarshipUNSPECIFIED
Wilf Family FoundationUNSPECIFIED
JPL President and Director's FundUNSPECIFIED
Subject Keywords:Astrophotonic spectrographs, Arrayed Waveguide Gratings, On-chip, Line Spread Function, Exoplanets
Series Name:Proceedings of SPIE
Issue or Number:12008
Record Number:CaltechAUTHORS:20220307-189697000
Persistent URL:
Official Citation:Marcos Perez, Pradip Gatkine, Nemanja Jovanovic, Jeffrey Jewell, J. Kent Wallace, and Dimitri Mawet "Simulating the study of exoplanets using photonic spectrographs", Proc. SPIE 12008, Photonic Instrumentation Engineering IX, 120080C (5 March 2022);
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:113782
Deposited By: George Porter
Deposited On:08 Mar 2022 23:15
Last Modified:12 Jul 2022 20:53

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