A new model for thermal radiation from spherical microparticles is presented. It treats small particles as volume emitters instead of the usual surface emitters to take into account the effect of temperature distributions inside the particle on emission. The model describes the spectral thermal emission of the particle’s volume cells as the radiation of classical electric dipoles with an averaged orientation in an absorbing dielectric sphere. Within this dipole model of thermal radiation Kirchhoff’s law is rederived. For nonisothermal temperature distributions inside particles, the angular dependence and the magnitude of the emitted radiation are computed. To test the influence of the model on the heat transfer in microparticles, we compare computed temperature distributions inside volume- and surface-emitting particles.
© 1994 Optical Society of America
S. Lange and G. Schweiger, "Thermal radiation from spherical microparticles: a new dipole model," J. Opt. Soc. Am. B 11, 2444-2451 (1994)