  The ALPS collaboration runs a "light shining through a wall" (LSW) experiment
to search for weakly interacting sub-eV particles (WISPs). Its sensitivity is
significantly enhanced by the incorporation of a large-scale production
resonator and a small-scale high-power resonant second harmonic generator. Here
we report on important experimental details and limitations of these resonators
and derive recommendations for further experiments. A very promising
improvement for a future ALPS experiment is the incorporation of an additional
large-scale regeneration resonator. We present a rough sketch of how to combine
a regeneration resonator with a single-photon counter (SPC) as detector for
regenerated photons.

Optics;High Energy Physics - Experiment