CHIRAL TWIST LASER AND FILTER APPARATUS AND METHOD

摘要

A defect causing a localized state is induced in a chiral structure (12) composed of multiple chiral elements (20, 22) by twisting one element of the chiral structure with respect to the other elements along a common longitudinal axis such that directors of the element molecular layers that are in contact with one another at contact area (26) are disposed at a particular "twist" angle therebetween, the twist angle being greater than a shift angle between directors of consecutive layers. The chiral twist structure may be utilized in a variety of applications such as filters, lasers and detectors. The defect caused by the twist may be made tunable by providing a tuning device for rotating one or more of the chiral elements with respect to one another to vary the twist angle and thus vary the position of the induced defect within a photonic stop band. Tunable defects may be advantageously utilized to construct tunable wavelength chiral filters, detectors and lasers.