Time dependence of the internal and scattered intensity of a dielectric sphere illuminated with a pulsed Gaussian beam

Abstract

The timedependent internal and scattered intensities of a dielectric sphere illuminated with a pulsed beam are presented. The incident beam is Gaussian in both space and time. The center of the beam is positioned inside, on the edge, or outside the sphere. The center frequency of the pulse is usually chosen so that the sphere is on or near a morphology-dependent resonance (MDR). The time-dependent fields at points inside or outside the sphere are calculated by inverse transforming the frequency spectrum. The frequency spectrum at each point is calculated by using the incident field spectrum and the transfer function at that point. The transfer function is the steady state field at the point of observation as a function of incident frequency. The steady state fields are calculated by using a combination of the plane wave spectrum technique and the T-matrix method. The primary factors determining the time dependence of the internal intensity are the position at which the intensity is computed; the position, spatial width, and temporal width of the incident Gaussian beam; the detuning of the center frequency of the pulse from the nearest high-Q MDR frequency; and the lifetime of the nearest high-Q MDR. The results help in modeling nonlinear optics in droplets.