The study centers around an injector with gas-dynamic fuel atomization, i.e. an emulsion atomizer, which is not widely spread as the operating processes inside its channel and at its outlet at critical values of gas pressures and temperatures are poorly studied. To test the performance of the atomizer, we measured the components’ concentration fields at the outlet by a non-contact optical method. Within the research, we specified the experimental research technique, which hinges on a change in the illumination intensity as a result of re-reflection of rays between particles when light passes through a cloud of atomized liquid. The technique makes it possible to fairly correctly determine the boundaries of liquid atomizing in a gas flow and the distribution of the relative flow rate along the spray height. Furthermore, we determined the minimum number of partition virtual zones, i.e. clouds, which give a sufficiently low calculation error. Finally, to confirm the applicability of the technique, we considered the distribution of the liquid supplied by the jet nozzle perpendicular to the airflow.