The possibility of measuring in-situ, operando photoluminescence spectroscopy within a photonic atom probe allows for real time study of the mechanical stress state within a field emitter either statically, as a function of the field-induced tensile stress or dynamically, as a result of the evolution of the shape of the emitter upon its evaporation. The dynamic evolution results from the relaxation of the strain induced by lattice mismatch and by the propagation of the stress from the apex while the morphology of the field emitter changes. The optomechanical information can be interpreted through the three-dimensional atomic scale images of the chemical composition of the emitter obtained through standard atom probe analysis. In the present work, the photoluminescence signal of a ZnO/(Mg,Zn)O quantum well allows for the local measurement of strain within the well and of the electrostatic field applied to the apex of the nanoscale field emitter.