DETERMINATION OF SIZE, REFRACTIVE-INDEX, AND DISPERSION OF SINGLE DROPLETS FROM WAVELENGTH-DEPENDENT SCATTERING SPECTRA

Intensities of light scattered in the planes parallel and perpendicular to the polarization plane of the incident light are used to determine the size, refractive index, and dispersion of a single droplet suspended in an electrodynamic balance. Wavelengths of TE- and TM-mode resonances are determined independently with high precision when a ring dye laser is scanned. Resonating wavelengths are matched with theoretical intensity peaks to determine the constants of a dispersion formula and the size that minimizes the difference between observed and calculated wavelengths. The procedure permits the determination of the size and refractive index with relative errors of 3 x 10(-5) and dispersion with an absolute error of 2 x 10(-5) over the experimental spectral range.