Axion dark matter detection by laser induced fluorescence in rare-earth doped materials

Caterina Braggio,Jordanka Tasseva,Giovanni Carugno,Pasquale Maddaloni,Federico Chiossi,Marco Guarise,Alberto Di Lieto,Luigi Santamaria,Mauro Tonelli,Antonello Ortolan,Giuseppe Ruoso

doi:10.1038/s41598-017-15413-6

Abstract

We present a detection scheme to search for QCD axion dark matter, that is based on a direct interaction between axions and electrons explicitly predicted by DFSZ axion models. The local axion dark matter field shall drive transitions between Zeeman-split atomic levels separated by the axion rest mass energy mac2. Axion-related excitations are then detected with an upconversion scheme involving a pump laser that converts the absorbed axion energy (~hundreds of μeV) to visible or infrared photons, where single photon detection is an established technique. The proposed scheme involves rare-earth ions doped into solid-state crystalline materials, and the optical transitions take place between energy levels of 4fN electron configuration. Beyond discussing theoretical aspects and requirements to achieve a cosmologically relevant sensitivity, especially in terms of spectroscopic material properties, we experimentally investigate backgrounds due to the pump laser at temperatures in the range 1.9 − 4.2 K. Our results rule out excitation of the upper Zeeman component of the ground state by laser-related heating effects, and are of some help in optimizing activated material parameters to suppress the multiphonon-assisted Stokes fluorescence.

Highlights

The nature of dark matter (DM) is the most long standing question in Big Bang cosmology, and direct searches may shed light on this intriguing mystery
The Axion Dark Matter eXperiment (ADMX) is the most sensitive haloscope detector based on high quality factor microwave resonators at cryogenic temperature
Single photon detection is required, and it can be realized by e.g. superconducting circuit devices acting as quantum bits properly coupled to the cavity photons[22,23], but as yet their dark count rate still exceeds the axion interaction rate

Summary

Introduction

The nature of dark matter (DM) is the most long standing question in Big Bang cosmology, and direct searches may shed light on this intriguing mystery. The Axion Dark Matter eXperiment (ADMX) is the most sensitive haloscope detector based on high quality factor microwave resonators at cryogenic temperature. The experiment HAYSTAC (formally ADMX-High Frequency)[20], designed to search for axions in the 20–100 μeV range (5–25 GHz), has recently reached cosmologically relevant sensitivity at 24 μeV (~5.8 GHz). Inhomogeneous filled cavities, in which the effective axion field is converted to magnetization oscillations of a ferrimagnet, are under study[21] In this case, single photon detection is required, and it can be realized by e.g. superconducting circuit devices acting as quantum bits properly coupled to the cavity photons[22,23], but as yet their dark count rate still exceeds the axion interaction rate

Methods

Results

Conclusion