Orbital and spin angular momentum Raman scattering of methanol, benzene, hexane, and carbon tetrachloride liquids

Spontaneous Raman spectra using Orbital angular momentum (OAM) and Spin angular momentum (SAM) from organic liquids with circularly polarized Laguerre-Gaussian (L= 1 and 2) were experimentally observed. Certain Raman peaks from vibrational bonds under circularly polarized OAM L= 1 and L= 2 mainly for CH3, and C-C arising from pi and sigma bonds were enhanced or decreased relative to the Raman of a Gaussian beam with L= 0. For example, methanol shows changes for circularly polarized OAM Raman ranging from 4.5% to 66.8% for different vibrational modes. The relevant enhancement and decrease in the Raman intensity from the various studied liquids are attributed to the matching up of the multipoles from the vibrational orbital structure from electron clouds symmetry with the multipoles of the OAM light. For example, Methanol and Hexane are more dipole-like (L=1); while Benzene is more quadrupole-like (L=2), and Carbon Tetrachloride is more monopole-like (L=0) in the interaction with L for OAM beams. In summary, we show that the use of OAM and SAM offers a new approach for larger changes of the Raman effect in contrast to circular dichroism and Raman optical activity methods, which have changes of less than 10−4.