Magneto Tunable Defect Modes in One-Dimensional Photonic Crystal Based on Magnetic Fluid Film

Abstract

AbstractIn the present communication we theoretically investigate and study the properties of defect modes in one dimensional defective photonic crystal (PC) based on magnetic fluid film (MFF). The magnetic fluid film (MFF) is a type of stable colloidal suspensions of magnetic nanoparticles. When the MFF is subjected to an external applied magnetic field, the nanoparticles form a chain along certain direction of magnetic field and its refractive index changes; this property of MFF can be used to tune the defect modes (transmission peaks) in PC. In this study, first, we take a PC structure composed of alternate layers of TiO2 and SiO2 and MFF (water based MnFe2O4 nanoparticles) as a defect layer having different porosity. In second case we take, two symmetric PC structure composed of alternate layers of MFF with different porosity and the effect of magnetic field on the surface mode (acts as a defect mode) has been studied. In order to calculate transmission spectra, we use transfer matrix method (TMM). Investigation of transmission curves show that tunability of defect modes (transmission peaks) are greatly influenced by magnetic field factor as well as the porosity of magnetic fluid film. This type of PC structure can be used to design the optical devices such as magnetic field sensors, tunable optical grating, optical switches, tunable narrow transmission filter, wavelength division multiplexer etc.KeywordsPhotonic crystalDefect modeTransmission modeMagnetic fluid filmTransmittance spectra