Sculptured thin films as ultranarrow-bandpass circular-polarization filters

In the Bragg wavelength-regime, a sculptured thin film with chiral micromor phology permits light of a particular circular polarization state to pass v irtually unhindered, but light of the other polarization state is reflected almost completely. This circular Bragg phenomenon is shown here to admit n arrow-band spectral reflection holes analogous to those well-studied as pha se defects within grating structures, Application to the design of an ultra narrow-bandpass circular-polarization filter is considered, with the locati on, bandwidth and polarization selectivity quantified via a particular set of numerical examples. (C) 1999 Elsevier Science B.V. All rights reserved.