Probing nonlinearity of semi-macroscopic vacuum by second harmonic generation with intense laser fields

Abstract

Astronomical observations suggest the presence of dark matter and dark energy. This may be attributable to undiscovered fields of small mass below 1eV [1,2,3]. These fields are thought to evade our effort to detect them in laboratory, because they are supposed to weakly couple to matter. The high intense laser fields may open up a new window for probing these fields via the coupling to laser photons with its degenerated feature and huge statistics per pulse. In this talk I present a novel method to search for these fields by observing second harmonic generation of photons in the quasi-parallel colliding system by focusing a single laser beam [4,5].