CMB Telescopes and Optical Systems

TL;DR

This review discusses optical components and design considerations for CMB telescopes, comparing ground-based, balloon, and satellite instruments, highlighting technological evolution and key experimental results in CMB observation.

Contribution

It provides a comprehensive overview of optical systems used in CMB measurements, comparing various instruments and highlighting advancements over three decades.

Findings

Comparison of ground-based telescopes like ACT and SPT.

Analysis of CMB satellite missions: COBE, WMAP, and Planck.

Discussion of optical design choices for different platforms.

Abstract

The cosmic microwave background radiation (CMB) is now firmly established as a fundamental and essential probe of the geometry, constituents, and birth of the Universe. The CMB is a potent observable because it can be measured with precision and accuracy. Just as importantly, theoretical models of the Universe can predict the characteristics of the CMB to high accuracy, and those predictions can be directly compared to observations. There are multiple aspects associated with making a precise measurement. In this review, we focus on optical components for the instrumentation used to measure the CMB polarization and temperature anisotropy. We begin with an overview of general considerations for CMB observations and discuss common concepts used in the community. We next consider a variety of alternatives available for a designer of a CMB telescope. Our discussion is guided by the ground and balloon-based instruments that have been implemented over the years. In the same vein, we compare the arc-minute resolution Atacama Cosmology Telescope (ACT) and the South Pole Telescope (SPT). CMB interferometers are presented briefly. We conclude with a comparison of the four CMB satellites, Relikt, COBE, WMAP, and Planck, to demonstrate a remarkable evolution in design, sensitivity, resolution, and complexity over the past thirty years.