Af. Molisch et al., RADIATION TRAPPING IN ATOMIC VAPORS IN FINITE-CYLINDER VAPOR CELLS EXCITED BY A LASER-BEAM, Journal of physics. B, Atomic molecular and optical physics, 30(8), 1997, pp. 1879-1891
We compute radiation trapping in a two-level atomic vapour excited by
a laser beam, taking into account saturation effects and using a reali
stic vapour-cell geometry, the finite cylinder. By using an approximat
ion for the angular distribution of the fluorescence radiation, CPU-ti
me requirements are kept low. We then analyse various practical cases
and present useful practical rules of thumb when certain simplificatio
ns are valid. When we consider the decay of an initial excitation, the
decay at late times can be computed by using an equivalent one-dimens
ional geometry. For early times, it is usually important to include th
e three dimensionality of the problem. Finally, we present calculation
s how the 'burn-through' effect of a strong laser affects the approxim
ation of the geometry.