Dielectric Haloscopes to Search for Axion Dark Matter: Theoretical   Foundations
  We study the underlying theory of dielectric haloscopes, a new way to detect dark matter axions. When an interface between different dielectric media is inside a magnetic field, the oscillating axion field acts as a source of electromagnetic waves, which emerge in both directions perpendicular to the surface. The emission rate can be boosted by multiple layers judiciously placed to achieve constructive interference and by a large transverse area. Starting from the axion-modified Maxwell equations, we calculate the efficiency of this new dielectric haloscope approach. This technique could potentially search the unexplored high-frequency range of 10--100 GHz (axion mass 40--400 $\mu$eV), where traditional cavity resonators have difficulties reaching the required volume. 
Alexander J. Millar, Georg G. Raffelt, Javier Redondo, Frank D.   Steffen
hep-ph astro-ph.CO astro-ph.HE hep-ex physics.ins-det