  Recently, it has been proposed that the fundamental scale of quantum gravity
can be close to the weak scale if there are large extra dimensions. This
proposal has important phenomenological implications for processes at the TeV
scale. We study the process gamma gamma -> gamma gamma, assuming an ultraviolet
cutoff M_S \sim 1 TeV for the effective gravity theory. We find that, at center
of mass energies \sqrt(s) \sim 1 TeV, the contribution of gravitationally
mediated scattering to the cross section is comparable to that coming from the
one-loop Feynman diagrams of the Standard Model. We thus conclude that the
effects of weak scale quantum gravity can be studied at the Next Linear
Collider (NLC), in the photon collider mode. Our results suggest that, for
typical proposed NLC energies and luminosities, the range 1 TeV \lsim M_S \lsim
10 TeV can be probed.
