The photoluminescence intensity of a light emitter embedded in an atom probe needle-shaped specimen varies with the morphological evolution of the latter during field evaporation. Light absorption and emission patterns within such an evolving system were calculated considering the increase in the reflectivity induced by the high electrostatic field present at the apex surface. A good agreement is obtained between the experimental and calculated photoluminescence intensity as a function of the evaporation progress. These methods could be applied to more general situations in which the properties of nanoscale objects are modulated by surface chemistry or morphology changes.