Resonance nonlinear optical properties of dye-doped liquid crystals under pulse excitation: Insight into early experiments

The results of studies of the nonlinear optical properties of dye-doped nematic (NLCs) and cholesteric liquid crystals (CLCs) under powerful laser excitation are presented. The invariability of the structure of a planar-oriented NLC as a result of the conservation of the absorption dichroism of an impurity dye under the control over the lasing threshold is shown. A method to reduce the threshold for the stimulated Raman scattering (SRS) in the isotropic phase of NLC at frequencies that overlap with the amplification band of a dissolved dye is proposed. The peculiarities of the energy characteristics of CLC lasers are studied in detail. A variation of the lasing efficiency and the nonlinear dependence of the lasing energy on the pumping are explained within a model of lasing systems with distributed feedback. The dynamics of the optical destruction of a planar texture of a dye-doped CLC at critically high levels of laser irradiation is studied. (C) 2018 Elsevier B.V. All rights reserved.