Detecting the Photon-Photon Interaction by Colliding Laser Beam Interferometry

The feasibility of detecting the photon-photon interaction using Fabry-Perot type laser interferometers developed for gravity wave detection is demonstrated. An external'' laser beam, serving as a refractive medium, is alternatively fed into the cavities of the interferometer and made to collide with the internal’’ beams thereby inducing a measurable phase difference between them.