Through the use of polarized light, it is possible to exploit the directional component of vibrational and electronic dipole moments in order to gain information relevant to molecular structure.
Electronic circular dichroism, or ECD, uses differing absorption of left and right-handed circularly polarized light in order to derive a CD spectrum. Molecules which are chiral exhibit different absorption of LCPL and RCPL leading to a CD spectrum. Large molecular structures such as protein and nucleic acids exhibit CD signals which are highly dependent on their super structure. A common use of ECD is the structural characterization of proteins. Nucleic acids are also typically studied via ECD to determine their tertiary structure.
In addition to differing absorption of LCPL and RCPL, some substances exhibit a peculiar property which is the emission of circularly polarized light. Circularly polarized luminescence, or CPL, entails the absorption of unpolarized light and the emission of circularly polarized light. Current research aims to exploit this property for use in optical devices and displays.
