Interplay between multiple scattering and optical nonlinearity in liquid crystals.

We discuss the role played by time-dependent scattering on light propagation in liquid crystals. In the linear regime, the effects of the molecular disorder accumulate in propagation, yielding a monotonic decrease in the beam spatial coherence. In the nonlinear case, despite the disorder-imposed Brownian-like motion to the self-guided waves, self-focusing increases the spatial coherence of the beam by inducing spatial localization.

Nematicon-driven injection of amplified spontaneous emission into an optical fiber.

We investigate experimentally the interaction between amplified spontaneous emission (ASE) and a soliton, which are both generated in a dye-doped nematic liquid crystal (LC) cell. A light beam is injected through an optical fiber slid into the cell to form a soliton beam. ASE is then automatically collected by this self-induced waveguide and efficiently coupled into the same optical fiber, in the backward direction.

A core copolymer approach to improve the gain properties of a red-emitting molecule.

We report a new approach to improve the gain characteristics of a red-emitting based molecule. The insertion of the active dye between two polymeric arms prevents the inter-molecular interactions deleterious for the gain. By means of the ultra-fast pump-probe technique we found an efficient energy transfer between the polymer and dye.