Present day "photon-collider experiments" at the low energy frontier probe
couplings corresponding to new physics at the multi 10 TeV scale. Such
physics has never been explored in the laboratory before, but constraints
from astrophysics rule out even lower couplings for specific types of WISPs
(weakly interacting sub-eV particles). In spite of this the necessity for
near future WISP hunting in the laboratory is shown and ways are sketched to
overcome astrophysics boundaries in the mid-term future. A long-term goal is
the sensitivity required to tackle the QCD axion.
"Light-shining-through-a-wall" experiments offer the most promising
perspectives.