Ultra wideband axion search using a Faraday haloscope

TL;DR

This paper proposes a novel ultra wideband axion detection method using a Faraday haloscope that exploits axion-induced magnetization and optical Faraday effect, enabling searches in previously inaccessible mass ranges with existing technology.

Contribution

It introduces a new experimental setup combining magnetic rods, optical cavities, and photon counting to detect axions across a broad mass spectrum, including high masses.

Findings

Potential to search for axions in the 500 to 5000 μeV range

Enhanced sensitivity through optical cavity confinement

Feasibility with current high-efficiency photon detectors

Abstract

Dark matter is a major constituent of our universe and the axion is a prime candidate. In this article, it is shown that by exploiting the axion induced magnetization in a magnetic rod and the Faraday effect, axions in the mass range $500$ to $5000~\mu$eV, a part of which ($> 3500~\mu$eV) is currently inaccessible to experiments, can be searched for using the same experimental setup in a year using the existing technologies. The magnetic rod is placed inside a high finesse optical cavity, which by confining the probe light inside it increases the interaction time and thus enhances the Faraday effect. This rotates the plane of polarization of the probe light sufficiently and produces a robust signal. Axions of different mass are selected using a dc magnetic field. Detection is carried out by counting photons in the optical domain using a readily available and high quantum efficiency ($\approx 1$) photon counter in a noise-free environment. An optical interferometric scheme that could provide spectroscopic information about the axion to be searched is also proposed.