Conversion of Dark Matter to Light in Multilayer Dielectric Haloscopes

The aim of optical halosopes is to detect dark matter particles in the local galactic halo by converting them to Standard Model photons. They are at the forefront of the current effort to directly detect bosonic cold dark matter that behaves like a classical field and may pervade the space around Earth.

We extend the Millar theoretical framework of 1D multilayer dielectric haloscopes developed to describe absorptive dielectric media with frequency-dependent complex refractive indices. Using this framework, we perform numerical calculations of the radiative signal power for various experimental setups driven by dark matter such as dark photons. In particular, we compare multilayer haloscopes using molecular gas layers to those using standard dielectrics. The refractive indices of the gases are reconstructed “resonance by resonance” using absorption data from HI-TRAN.

The sharp frequency dependence of molecular resonances, which can be finely tuned in laboratory settings, can lead to numerous experimental advantages. However, we find that absorption from molecular resonances can significantly diminish the boost factor (relative enhancement of the optical signal power) of multilayer dielectric haloscope dark matter detectors.