Light-Shining-Through-Walls Experiments

Abstract

AbstractThe light-shining-through-walls (LSW) method of searching for ultralight bosonic dark matter (UBDM) uses lasers and strong dipole magnets to probe the coupling between photons and UBDM in the presence of a magnetic field. Since these experiments take place entirely in the laboratory, they offer a unique opportunity to perform a model independent measurement of this interaction. This involves shining a high-power laser through a magnetic field toward a wall which blocks the light. The interaction between the laser and the magnetic field generates a beam of UBDM that passes through the wall. Beyond the wall is another region of strong magnetic field that reconverts the UBDM back to photons that can then be measured by a single photon detection system. The sensitivity of these kinds of experiments can be improved further by implementing optical cavities before and after the wall to amplify the power of the light propagating through the magnetic fields. This chapter gives an introduction to LSW experiments and discusses a number of interesting challenges associated with the technique.