Transient Defect Mode based on Local Deformation of Helix

Abstract

The photonic defect modes in a cholesteric liquid crystal induced by a local deformation of its helix has been investigated. The defect modes appear in transmission spectra only when incident circularly polarized light has the same handedness as the helix. The tuning of defect mode position can be performed upon both local expansion and squeeze of helix, in which the shift direction of the defect mode wavelength is opposite. Upon controlling the degree of the deformation of helix, continuous shift of defect modes can be realized.