Renormalization of polaritons due to the formation of excitonic molecules in CuCl; an experimental aspect

Abstract

The modulation of the real part of the non-linear refractive index (Δn) associated with the giant two-photon absorption (GTA) band of the excitonic molecules (EM's) has been measured in CuCl at 1.6K. This has been measured by the observation of the polarization rotation effects due to the induced optical anistropy between the right circularly polarized (σ + ) and the left circularly polarized (σ - ) components of the linearly polarized probe team of Ω 1 under the strong irradiation of the σ - beam of Ω 2 fixed around the GTA band at 3.1861 eV. The maximum amount of Δn has been 2.9×10 -4 at 3.1920 eV under the maximum excitation level when Ω 2 has been fixed at 3.1796 eV. The experimental results have been discussed in terms of the renormalization of the polaritons due to the real and virtual formation of EM's.