  We incorporate the effects of fluctuations in a density functional analysis
of the freezing of a colloidal liquid in the presence of an external potential
generated by interfering laser beams. A mean field treatment, using a density
functional theory, predicts that with the increase in the strength of the
modulating potential, the freezing transition changes from a first order to a
continuous one via a tricritical point for a suitable choice of the modulating
wavevectors. We demonstrate here that the continuous nature of the freezing
transition at large values of the external potential $V_{e}$ survives the
presence of fluctuations. We also show that fluctuations tend to stabilize the
liquid phase in the large $V_{e}$ regime.
