Modeling sidelobe response for ground-based mm-wavelength telescopes with the geometrical theory of diffraction

Image credit: Fig 1

Abstract

Accurate optical modeling is important for the design and characterisation of current and next-generation experiments studying the Cosmic Microwave Background (CMB). Geometrical Optics (GO) cannot model diffractive effects. In this work, we discuss two methods that incorporate diffraction, Physical Optics (PO) and the Geometrical Theory of Diffraction (GTD). We simulate the optical response of a ground-based two-lens refractor design shielded by a ground screen with time-reversed simulations. In particular, we use GTD to determine the interplay between the design of the refractor’s forebaffle and the sidelobes caused by interaction with the ground screen.

Publication
Part of SPIE Proceedings Volume 11453, Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy
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Alexandre Adler
Alexandre Adler
PhD Student

My research focuses on how to best model beam-related systematics for various experiments.

Jón E. Guðmundsson
Jón E. Guðmundsson
Assistant Professor

Assistant professor at the University of Iceland and senior research scientist at Stockholm University.