The OSQAR photon regeneration experiment searches for pseudoscalar and scalar axion-like particles by the method of Light Shining Through a Wall, based on the assumption that these weakly interacting sub-eV particles couple to two photons to give ris
e to quantum oscillations with optical photons in strong magnetic field. No excess of events has been observed, which constrains the di-photon coupling strength of both pseudoscalar and scalar particles down to $5.7 cdot 10^{-8}$ GeV$^{-1}$ in the massless limit. This result is the most stringent constraint on the di-photon coupling strength ever achieved in laboratory experiments.
