  In this letter, we investigate the effect of orbital angular momentum (OAM)
on elastic photon-photon scattering in vacuum for the first time. We define
exact solutions to the vacuum electro-magnetic wave equation which carry OAM.
Using those, the expected coupling between three initialwaves is derived in the
framework of an effective field theory based on the Euler-Heisenberg
La-grangian and shows that OAM adds a signature to the generated photons
thereby greatly improvingthe signal-to-noise ratio. This forms the basis for a
proposed high-power laser experiment utilizingquantum optics techniques to
filter the generated photons based on their OAM state
