Dielectric Haloscopes: A New Way to Detect Axion Dark Matter
  We propose a new strategy to search for dark matter axions in the mass range
of 40--400 $\mu$eV by introducing dielectric haloscopes, which consist of
dielectric disks placed in a magnetic field. The changing dielectric media
cause discontinuities in the axion-induced electric field, leading to the
generation of propagating electromagnetic waves to satisfy the continuity
requirements at the interfaces. Large-area disks with adjustable distances
boost the microwave signal (10--100 GHz) to an observable level and allow one
to scan over a broad axion mass range. A sensitivity to QCD axion models is
conceivable with 80 disks of 1 m$^2$ area contained in a $10$ Tesla field.
