2023 Astrophotonics Roadmap: pathways to realizing multi-functional integrated astrophotonic instruments
Nemanja Jovanović, Pradip Gatkine, Narsireddy Anugu, Rodrigo Amezcua‐Correa, R. Basu Thakur, Charles Beichman, Chad F. Bender, Jean-Philippe Berger, Azzurra Bigioli, Joss Bland‐Hawthorn, Guillaume Bourdarot, Charles M. Bradford, R.G. Broeke, Julia J. Bryant, Kevin Bundy, Ross Cheriton, Nick Cvetojević, Momen Diab, Scott A. Diddams, Aline N. Dinkelaker, Jeroen Duis, Stephen S. Eikenberry, Simon Ellis, Akira Endo, Donald F. Figer, Michael P. Fitzgerald, Itandehui Gris-Sánchez, Simon Gross, Ludovic Grossard, Olivier Guyon, Sebastiaan Y. Haffert, Samuel Halverson, Robert J. Harris, Jinping He, Tobias Herr, Philipp Hottinger, Elsa Huby, Michael Ireland, Rebecca Jenson-Clem, Jeffrey Jewell, L. Jocou, Stefan Kraus, Lucas Labadie, S. Lacour, Romain Laugier, K Katarzyna Lawniczuk, Jonathan Lin, Stephanie Leifer, Sergio G. Leon-Saval, Guillermo Martín, Frantz Martinache, Marc-Antoine Martinod, Benjamin A. Mazin, Stefano Minardi, John D. Monnier, Reinan Moreira, D. Mourard, Abani Shankar Nayak, Barnaby Norris, Ewelina Obrzud, K. Perraut, François Reynaud, Steph Sallum, David Schiminovich, Christian Schwab, Eugene Serbayn, Sherif Soliman, Andreas Stoll, Liang Tang, Peter Tuthill, Kerry J. Vahala, Gautam Vasisht, Sylvain Veilleux, Alexander B. Walter, Edward J. Wollack, Yinzi Xin, Zongyin Yang, Stephanos Yerolatsitis, Yang Zhang, Chang‐Ling Zou
Abstract
Abstract Photonic technologies offer numerous functionalities that can be used to realize astrophotonic instruments. The most spectacular example to date is the ESO Gravity instrument at the Very Large Telescope in Chile that combines the light-gathering power of four 8 m telescopes through a complex photonic interferometer. Fully integrated astrophotonic devices stand to offer critical advantages for instrument development, including extreme miniaturization when operating at the diffraction-limit, as well as integration, superior thermal and mechanical stabilization owing to the small footprint, and high replicability offering significant cost savings. Numerous astrophotonic technologies have been developed to address shortcomings of conventional instruments to date, including for example the development of photonic lanterns to convert from multimode inputs to single mode outputs, complex aperiodic fiber Bragg gratings to filter OH emission from the atmosphere, complex beam combiners to enable long baseline interferometry with for example, ESO Gravity, and laser frequency combs for high precision spectral calibration of spectrometers. Despite these successes, the facility implementation of photonic solutions in astronomical instrumentation is currently limited because of (1) low throughputs from coupling to fibers, coupling fibers to chips, propagation and bend losses, device losses, etc, (2) difficulties with scaling to large channel count devices needed for large bandwidths and high resolutions, and (3) efficient integration of photonics with detectors, to name a few. In this roadmap, we identify 24 key areas that need further development. We outline the challenges and advances needed across those areas covering design tools, simulation capabilities, fabrication processes, the need for entirely new components, integration and hybridization and the characterization of devices. To realize these advances the astrophotonics community will have to work cooperatively with industrial partners who have more advanced manufacturing capabilities. With the advances described herein, multi-functional integrated instruments will be realized leading to novel observing capabilities for both ground and space based platforms, enabling new scientific studies and discoveries.