Spontaneous emission in the ellipsoidal nanocrystals

The equation was presented for the spontaneous emission rate A_nano of the two-level optical centers in the subwavelength ellipsoidal nanocrystals embedded in a dielectric medium. An important result was that the ratio A_nano/A_bulk could be estimated without recourse to a particular local-field model. On the ground of this equation the expression was derived for linestrength of electric-dipole transition in trivalent rare-earth ions. The applicability of the Judd-Ofelt equation for nanoparticles was discussed.