A final note is that the discussion above concerns the simulation of the true ECD and CPL signals in chiral extended materials. However, experimental measurements are plagued by interference from macroscopic anisotropies in the solid state, i.e, linear dichroism (LD) and linear birefringence (LB), see for instance Ref. 6 for a more detailed discussion. One interference effect appears when the main axes of LD and LB do not align; this is a real effect in the sense that it is not due to the instrument. Other effects are instrumental artifacts that can be due to the polarization modulation technique or the photomultiplier.