Three-pulse photon-photon scattering

We calculate signals of real photon-photon scattering in the collision of three laser pulses. Taking goal parameters from the Station of Extreme Light at the upcoming Shanghai Coherent Light Source, we consider two scenarios: i) the collision of three optical pulses; ii) the collision of an XFEL with two optical pulses. Although experimentally more difficult to perform, we find that colliding three laser pulses offers certain advantages in the detection of scattered photons by separating their frequency, momentum and polarisation from the background.