  Dilepton production from two photon interactions $\gamma\gamma\rightarrow
l^+l^-$ are studied in semi-central and peripheral nuclear collisions. Based on
Weizs\"acker-Williams approach, it is shown that the dilepton photoproduction
is proportional to the electromagnetic (EM) fields $\sim E^2B^2$ and therefore
sensitive to the magnitude and lifetime of initial EM fields which last only
for a short time and are hard to be measured in experiments directly. We
propose dilepton photoproduction as a probe for the nuclear charge
fluctuations, which are crucial for the electric/magnetic field induced chiral
and charge particle evolutions. We calculate the relative standard deviation of
dilepton mass spectrum with event-by-event fluctuating nuclear charge
distributions (and EM fields).
