Study of Band Gap Tunablity in one-dimensional Photonic Crystals of Multiferroic-dielectric materials: Case Study in Near Infrared Region

Abstract

In the investigation, the photonic band gap (PBG) is numerically analyzed in the infrared frequency region from the reflectance, calculated by the transfer matrix methods from the various angles of the incidence, number of the periods in the PC and the nature/ geometry of the existing materials. Out of the various photonic materials, the main work is focused on polar oxide like Bi(Fe1−xMnx)O3, which have been alternately arranged with dielectric materials like SrTiO3 or DyScO3. The tunable characteristics are studied by changing with the replacement of Fe+3 from BFO lattice with Mn+3. The substitution of Mn+3 at the place of Fe+3 forms a solid solution with the parent BFOhost lattice. The absorption response of the mixed metal solid solutions is approximately a linear combination of the characteristics of the two end members; as a result that demonstrates straightforward band gap tunability in polar oxides. The tunability is observed in a red-shift by varying the percentage of Mn+3 in the BFO lattice. The effect of the number of periods with different dielectric material on the photonic band gap is illustrated. Using Transfer Matrix Method (TMM) and Bloch theorem, the reflectivity of one dimensional periodic structure for TE and TM-modes at different angles of incidence has also been calculated. The band gap enlargement due to the addition of the Mn+3 atoms in BFO lattice is illustrated in the case of normal incidence and a wider omnidirectional band gap can be obtained beyond 30o angle of incidence.