  We have shown that it is possible to model accurately optical phenomena in
intense laser fields by taking into account the intensity distribution over the
laser beam. We developed a theoretical model that divided an intense laser beam
into concentric regions, each with a Rabi frequency that corresponds to the
intensity in that region, and solved a set of coupled optical Bloch equations
for the density matrix in each region. Experimentally obtained magneto-optical
resonance curves for the $F_g=2\longrightarrow F_e=1$ transition of the $D_1$
line of $^{87}$Rb agreed very well with the theoretical model up to a laser
intensity of around 200 mW/cm$^2$ for a transition whose saturation intensity
is around 4.5 mW/cm$^2$. We have studied the spatial dependence of the
fluorescence intensity in an intense laser beam experimentally and
theoretically. An experiment was conducted whereby a broad, intense pump laser
excited the $F_g=4\longrightarrow F_e=3$ transition of the $D_2$ line of cesium
while a weak, narrow probe beam scanned the atoms within the pump beam and
excited the $D_1$ line of cesium, whose fluorescence was recorded as a function
of probe beam position. Experimentally obtained spatial profiles of the
fluorescence intensity agreed qualitatively with the predictions of the model.
