Resonance structure of composite and slightly absorbing spheres

Using optical levitation of individual 3-10-/Lm droplets, we investigate the resonance structure of the light intensity scattered at an angle of approximately 900 by a dielectric droplet, a slightly absorbing droplet, and composite inhomogeneous droplets. We find in all the cases that the resonance structures of dielectric, weakly absorbing, and composite inhomogeneous spheres are almost identical for the imaginary part of the refractive index (or of an effective refractive index for the case of a composite sphere) smaller than 10-5. Thus a small amount of highly absorbing material dispersed in a dielectric sphere does not destroy its resonance characteristics.