Spectral hole burning in crystalline Eu 2O 3 and Y 2O 3 : Eu 3+ nanoparticles

Abstract

Optical dephasing of nanoparticles of Eu 2O and Y 2O 3 : Eu 3+ is studied, using transient spectral hole burning, as a function of temperature and particle size, d. A strongly enhanced optical dephasing rate is observed whose magnitude depends on 1 d 2 . This is interpreted as an enhancement of the electron-phonon interaction. A calculation for the two-phonon Raman scattering rate, which includes a smoothed phonon density of states for a nanoparticle. describes the nearly exponential temperature dependence of the hole line width, but does not properly describe the particle size dependence. A more complete theory which takes into account the spatial dependence of the amplitude of the phonon surface modes is required.