SELECTION STRATEGY FOR CIRCULAR-POLARIZATION-SENSITIVE REJECTION CHARACTERISTICS OF ELECTRO-OPTIC AMBICHIRAL REUSCH PILES

Open Access
Author:
Dixit, Mukul
Graduate Program:
Engineering Science
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
June 12, 2008
Committee Members:
  • Akhlesh Lakhtakia, Thesis Advisor
Keywords:
  • ambichiral
  • Bragg
  • Reusch pile
Abstract:
The circular-polarization-sensitive rejection characteristics of an electro-optic ambichiral Reusch pile can be selected in a chosen wavelength regime by properly choosing the thickness of the layers in the pile. The Pockels effect can, in most cases, increase the effective birefringence in the copolarized reflectance spectrums of an electro-optic ambichiral Reusch pile, when a dc electric field is applied. If a dc electric field is applied to the Reusch pile, the circular Bragg phenomenon converts to a polarization independant Bragg phenomenon for large angle of incidences. Furthermore, if a dc electric field is not applied to the ambichiral Reusch pile, the circular Bragg phenomenon never converts to a polarization-independent Bragg phenomenon, although it still vanishes for large angle of incidences. Also, the value of the angle of incidence at which the circular Bragg phenomenon converts to a polarization–independent Bragg phenomenon depends on both the magnitude and the direction of the applied dc electric field. An electrically controllable spectral-hole filter can be devised by inserting a central twist defect in an ambichiral Reusch pile. The application of a dc electric field also affects the circular-polarization-sensitive rejection characteristics of an ambichiral Reusch pile with a central twist defect in it.