# Feasibility of Cosmic Microwave Background Observations using Radiometers based on Whispering Gallery Mode Resonators

## TL;DR

This paper explores the potential of whispering gallery mode resonators for building room-temperature radiometers aimed at cosmic microwave background observations, highlighting both promising aspects and current limitations.

## Contribution

It proposes a novel spectro-polarimeter design based on WGM resonators and evaluates its feasibility through simulations compared to existing technologies.

## Key findings

- WGM resonator-based radiometers show promise but require further R&D.
- Simulations indicate potential advantages over traditional coherent receivers.
- Current limitations prevent immediate competitiveness, guiding future research directions.

## Abstract

The fundamentals of the whispering gallery mode (WGM) resonators are well established in the literature, with several successful proof-of-concept experiments. One remarkable benefit of this technology is the room-temperature operation. This characteristic could be used to build a new generation of radiometers that do not need to be cooled down to cryogenic temperatures to reach high sensitivities. In this article, a study of the viability of technological transfer is undertaken, beginning with a brief review of the theoretical background that will be applied and leading to a proposal for a novel spectro-polarimeter design. Simulations for a radiometer based on WGM resonance are analyzed and compared with state-of-the-art coherent receivers. The results are then discussed, finding that although promising, WGM technology needs R\&D in several directions in order to be competitive, whose are suggested by the authors with the idea of inspiring the work of the researchers in the field towards a new direction or approach.