Non-linear optical spectroscopy of single molecules in solids at low temperatures

Abstract

We report on pump-probe experiments on single molecules in a solid matrix, with strong laser fields and on a new host-guest system, dibenzanthanthrene in a naphthalene crystal. Besides strong light-shifts of the molecular lines, we observe the hyper-Raman resonance and for strong pump and probe beams, we also observe subharmonic resonances due to a ‘kicked pendulum’ motion of the Bloch vector. The experimental results are in very good agreement with calculations based on Bloch's equations, demonstrating their validity for single molecules in solids under intense resonant fields.