Helical structures light propagation

Fig. 38 General mechanism of the nucleation and elongation stages of polymerization generating a helical structure (the arrows represent the interactions among repeating units). Secondary interactions light arrows), absent in the first turn of the helix, are the molecular origins of a less favorable nucleation event (i.e.,the critical chain length) beyond which propagation becomes more favorable...

Fig. 12.6 Dispersion relation for a cholesteric that has helical structure with wavevector qo. The abscissa corresponds to the wavevectors of the eigenmodes propagating in the medium and the ordinate is the frequency of the incident light proportional to its wavevector, k = (a) Very...

In order to find such an approximation we return for a moment to the problem of light propagation in a helical structure. In the foregoing discussion the limit of long pitches, A/p C — n, was excluded. As a matter of fact this limit was considered as early as 1911 by Maugin and was treated by de Vries also. They showed that in this regime the normal modes become linearly polarized one is... 

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