In all other emission directions ($\vartheta\neq\frac{\pi}{2}$) the induced photons originating from the stimulated emission process are polarized differently than the laser, implying that basically all emitted photons are polarized differently than the laser beam triggering the effect.

In turn, this could be used to distinguish the signal (emitted photons) from the laser photons of the same frequency. For example, equipping a photon detector with a polarizer blocking the polarization of the laser beam along $\vec{e}_{\rm x}$ still a significant fraction of the total numbers of photons emitted in directions outside the laser beam, $N^\Omega_{{\rm tot},>}$, should be detectable: All photons with a nonvanishing polarization component perpendicular to $\vec{e}_{\rm x}$ will actually contribute to the signal. With respect to such measurement, our result  for the truly perpendicular polarized emission signal $N^\Omega_{\perp,>}$ (cf. also Fig. \[fig:Nperpx\] and Tab. \[tab:lasers\]) just amounts to the absolute minimum number of emitted photons to be detected.

Conclusions and Outlook {#seq:Con+Out}
=======================

In this paper we have studied and interpreted a specific laser pulse collision process in terms of stimulated single photon emission from the vacuum in strong space-time dependent electromagnetic fields. More specifically, we have focused on a particular field configuration mimicking the electromagnetic field in 