Abstract
We report on an experimental assessment of the generally weak coupling of the electromagnetic phases of structured light to matter. Using a systematic study of a liquid crystal series including plasmonic particles, we optimized the reflectivity of the chiral phase, leading to a high sensitivity and discrimination of orbital angular momenta states of light. The involved inelastic scattering shows a decisive dependence of its energy on scattering vectors in comparing different scattering geometries (transmission and backscattering), and of intensity on fine-tuning the ratio of cholesteryl nonanoate (CN) doped with cholesteryl chloride (CC), CN:xCC. We provide spectroscopic evidence for an important role of geometric resonances of the light wavelength with the chiral pitch length and propagation vector, p(T, x), of the liquid crystal. We show that inelastic scattering originates from an exchange process, which is identified by momentum transfer. Tailoring the materials, adding plasmonic effects, and optimizing the laser wavelength, we managed to enhance the low energy response by 42 and 71%, respectively. The role of long-range dipolar interactions as well as geometric and electronic resonances are discussed to dominate these processes and their characteristic energy scales. Our work adds an interesting aspect to potential applications of liquid crystals in advanced photonics such as relevance for enhanced information transfer and communication.