  Light-shining-through-walls experiments are the search experiments for weakly
interacting slim particles (WISPs) with the smallest model dependence. They
have the advantage that not only the detection, but also the production of the
WISPs takes place in the laboratory and can thus be controlled. Using lasers is
the preferred option for most of the mass region and has led to the world's
most stringent laboratory limits (ALPS I) there. At CERN, OSQAR promises to
surpass these and at DESY ALPS II is currently set up, which is planning to
probe the axion-like particle to photon coupling down to $|g_{a\gamma}|\gtrsim
2\cdot10^{-11}$ GeV$^{-1}$, which is in a region favored by many astrophysical
hints.
