Freeform three-mirror anastigmatic large-aperture telescope and receiver optics for CMB-S4
astro-ph.IM
/ Authors
Patricio A. Gallardo, Roberto Puddu, Kathleen Harrington, Bradford Benson, John Carlstrom, Simon R. Dicker, Nick Emerson, Jon E. Gudmundsson, Michele Limon, Jeff McMahon
and 7 more authors
Johanna M. Nagy, Tyler Natoli, Michael D. Niemack, Stephen Padin, John Ruhl, Sara M. Simon, the CMB-S4 collaboration
/ Abstract
CMB-S4, the next-generation ground-based cosmic microwave background (CMB) observatory, will provide detailed maps of the CMB at millimeter wavelengths to dramatically advance our understanding of the origin and evolution of the universe. CMB-S4 will deploy large and small aperture telescopes with hundreds of thousands of detectors to observe the CMB at arcminute and degree resolutions at millimeter wavelengths. Inflationary science benefits from a deep delensing survey at arcminute resolutions capable of observing a large field of view at millimeter wavelengths. This kind of survey acts as a complement to a degree angular resolution survey. The delensing survey requires a nearly uniform distribution of cameras per frequency band across the focal plane. We present a large-throughput, large-aperture (5-meter diameter) freeform three-mirror anastigmatic telescope and an array of 85 cameras for CMB observations at arcminute resolutions, which meets the needs of the delensing survey of CMB-S4. A detailed prescription of this three-mirror telescope and cameras is provided, with a series of numerical calculations that indicate expected optical performance and mechanical tolerance.