Born–Kuhn coupled oscillator model for optical activity in ordered media

Considering the phenomenological electromagnetic description of optical activity, we establish a unified formal framework, wherein the gyration and permittivity tensors of any ordered medium (a molecule or a crystal) can be derived using the classic Born-Kuhn coupled oscillator model. This model allows for efficient parameterisation of both tensors in terms of configurational and structural parameters (orientations, positions and coupling strengths) of a system of coupled oscillators having the same symmetries as the medium of interest. Thus, Born-Kuhn molecular models of all optically active crystal classes are established.