DROPLET DIAMETER AND THE INTERFERENCE-FRINGES BETWEEN REFLECTED AND REFRACTED LIGHT

The geometric optics model of light scattering from droplets is based on the interference of the reflected and refracted light. Although the relationships are regularly quoted, we have found that the assumption s in the underlying derivations are incorrect, In this rapid communica tion, we derive the correct optical path difference between reflected and refracted beams scattered from a droplet. Furthermore, we show tha t the standard form used for the scattering factor relating the fringe separation to the droplet diameter is wrong-we derive the correct ana lytical result, which leads to a correction in droplet-size calculatio ns based on optical measurements.