  We investigate in detail the stimulated photon emission in pulse-shaped
Laguerre-Gauss beams of arbitrary mode decomposition within the framework of
Euler-Heisenberg effective theory. We elaborate on the analytic structure of
the photon emission amplitude and identify its dominant and sub-dominant parts
by analyzing each signature's phase scaling. We identify three distinct
nonlinear signatures: the orbital angular momentum (OAM) flip ($\ell:1
\rightarrow -1$) , higher harmonic generation ($\ell:1 \rightarrow 2$) and
harmonic reduction ($\ell:1 \rightarrow 0$). We estimate signal photon yield
for each signature under various pulse collision scenarios we explain in
detail. We also outline a prospective experimental setup that may probe these
signatures.
