  We use vortex photon fields with orbital and spin angular momentum to probe
chiral fluctuations within liquid crystals. In the regime of iridescence with a
well-defined pitch length of chirality, we find low energy Raman scattering
that can be decomposed into helical and chiral components depending on the
scattering vector and the topological charge of the incident photon field.
Based on the observation of an anomalous dispersion we attribute quasi-elastic
scattering to a transfer of angular momenta to roton-like quasiparticles. The
latter are due to a competition of short-range repulsive and long-range dipolar
interactions. Our approach using a transfer of orbital angular momentum opens
up an avenue for the advanced characterization of chiral and optically active
devices and materials.
