Raman scattering from orbital and spin angular momentum in materials

Abstract

A method for obtaining a polarized orbital angular momentum Raman spectrum using vector vortex beams, includes the steps of emitting a polarized laser light from a laser source. The polarized laser light is passed through a narrow band filter that is then passed through a section of wave plates (quarter or half wave plate) to generate polarized light (linear, circular, radial and azimuthal), then through a q-plate (vortex retarder or spiral plate) to give a vortex structure topology carrying orbital angular momentum with a helical phase. The polarized vector vortex light is then directed to contact a sample, thereby producing a Raman scatter beam. The Raman scatter beam is passed back and collected into a spectrometer, thereby obtaining a Raman scattering spectrum of the sample to investigate the matching of the multipoles of the material and the multipoles of the light. A method for transmission with Multiple expansions of orbital angular momentum in rat cerebellum tissue is also disclosed. In general, we use polarized Laguerre-Gaussian vector vortex beams as a topology multipole model to describe and study the light matter interaction for Raman and transmission using the fact that the optical vortices and material can possess Multipoles denoted as L in form of monopole (L=0), dipole (L=1), quadrupole (L=2), octupole (L=3), hexidecapole (L=4) and higher orders. These multipoles can be involved with the matching up with the symmetry of the moments involved with vibrational states in Raman processes.