Internal electromagnetic energy within a dielectric sphere in a plane-polarized TEM_00 laser beam

Abstract

An analytical expression for the time-averaged electromagnetic energy within a dielectric sphere in a plane-polarized TEM00 laser beam, which is of importance for the study of photochemical reactions of an optically levitated sphere, is derived by using a theory of Hermite–Gaussian-mode laser-beam scattering by spheres. The result is also generalized to that for a plane-polarized TEM00 laser beam. Numerical calculations of the electromagnetic energy are carried out for a left-circularly polarized TEM00 laser beam, and the results are compared with plane-wave results. At resonances, the electromagnetic energy for a plane wave is shown to exceed by an order of magnitude that for a TEM00 laser beam of focal spot radius W0 = 5λ. This supports the fact that partial wave resonances result from photons traveling around a sphere surface.