Polarization-Entangled Two-Photon Absorption in Inhomogeneously Broadened Ensembles

Abstract

Entangled photons are promising candidates for a variety of novel spectroscopic applications. In this paper, we simulate two-photon absorption (TPA) of entangled photons in a molecular ensemble with inhomogeneous broadening. We compare our results with a homogeneously broadened case and comment on the consequences for the possible quantum enhancement of TPA cross sections. We find that, while there are differences in the TPA cross section, this difference always remains small and of the order unity. We further consider the impact of the polarization degrees of freedom and carry out the orientational average of a model system Hamiltonian. We find that certain molecular geometries can give rise to a substantial polarization dependence of the entangled TPA rate. This effect can increase the TPA cross section by up to a factor of five.