Elastic light scattering from single microparticles on a femtosecond time scale

Experimentally measured and theoretically calculated elastic light-scattering spectra from single microparticles illuminated by 100-fs pulses are presented. Although in the theoretical calculation only a single incoming femtosecond laser pulse was used, the spectral behavior of scattered light shows all the features seen in the experimental spectrum from many femtosecond pulses, including morphology-dependent resonances (MDR's). The good agreement between experimental and theoretical elastic light-scattering data has stimulated a theoretical investigation of the time-dependent behavior of the elastically scattered light from a single microparticle on a femtosecond time scale. Since the spatial pulse length of the incoming laser pulse is smaller than the particle circumference, the temporal behavior of reflection, diffraction, refraction, and coupling into MDR's can be distinguished. Since the time-dependent scattering is strongly dependent on particle size, refractive index, and pulse chirp, it may be possible to encode several bits of information into a single laser pulse and therefore to increase optical data communication rates.