Two-photon process via internal conversion by correlated photon pairs

Abstract

We theoretically investigate a two-photon process via molecular internal conversion, driven by correlated photons with time delay. As an example, a molecular system approximated by Morse oscillators is used in order to evaluate the efficiency of the process, in terms of how the efficiency changes with the nonadiabatic coupling rate of vibronic states. We show that an efficient two-photon process requires two different correlated photon pairs with positive and negative energy correlations, depending on the value of the nonadiabatic coupling rate.

Nonlinear optical signals and spectroscopy with quantum light

“…So far, we have not discussed how the overall excitation probability by entangled light sources compares to classical light with similar photon flux. This is relevant to recent demonstration of molecular internal conversion (Oka, 2012) and two-photon absorption with the assistance of plasmonics (Oka, 2015). This is a very important practical point, if quantum spectroscopy is to be carried out at these very low photon fluxes, in the presence of additional noise sources.…”

Entangled photon spectroscopy

“…The impact of frequency correlations in two-photon transitions was also discussed in the context of quantum dots [123], or in the excitation of vibronic states [124], opening the possibility to control chemical reactions [125]. Internal conversion processes can also be investigated [126].…”

“…The impact of frequency correlations in two-photon transitions was also discussed in the context of quantum dots [119], or in the excitation of vibronic states [120], opening the possibility to control chemical reactions [121]. Internal conversion processes can also be investigated [122]. Given the tremendous success of multidimensional laser spectroscopy we had mentioned in the introduction, it would certainly be very appealing to combine the strong correlation effect with multidimensional techniques.…”