Optical trapping and spectral analysis of aerosols with a supercontiuum laser source

We report on the optical trapping of water droplets with a supercontinuum laser source. Droplet size is determined by observing the spectrum of the on-axis backscattered light. In contrast to to monochromatic trapping, the broad spectrum of the supercontinuum covers several resonances of the first excited Mie coefficients. A minimum value of Q similar to 0.16 for the trapping efficiency is estimated. (C) 2008 Optical Society of America.