Electrically tunable optical properties of one-dimensional photonic crystal containing nanocomposite structurally chiral material

Abstract

In the present paper, the reflection and transmission properties of a one-dimensional photonic crystal made of alternate layers of isotropic dielectric medium and electro-optic nanocomposite structurally chiral medium (NSCM) are investigated. The electro-optic NSCM is a nanocomposite medium consisting structurally chiral material (SCM) where the silver nanoparticles are randomly dispersed inside it. The numerical results show three kinds of photonic bandgap in this structure, including traditional Bragg gap, circular Bragg gap and plasmonic absorption bandgap, which is due to the plasmonic resonance and absorption of the silver nanoparticles. The effect of the external low-frequency electric field is investigated on the reflection and transmission spectra of the structure. It is shown that the impact of the applied voltage depends on the value of the tilt angle and the maximum changes are experienced for the case of \(\chi = 90^\circ\). Also, the results show that the width of the traditional and circular Bragg gaps is sensitive to the applied voltage; however, the variation of the circular Bragg gap is more noticeable.