We propose all-optical tests of photon-photon interactions in the matter vacuum using standing-wave laser interferometers, which do not require external magnetic fields and use conventional laser sources. We show that the interferometric detection of
We propose all-optical tests of photon-photon interactions in the matter vacuum using standing-wave laser interferometers, which do not require external magnetic fields and use conventional laser sources. We show that the interferometric detection of photon-photon scattering predicted by quantum electrodynamics is within reach of laboratory-scale experiments with a sensitivity that improves nonlinearly with the circulating power within the cavity. We outline how such an experiment could be adapted to probe properties of quantum fields beyond the Standard Model of particle physics.