Tunable reflectance characteristics of magnetized cold plasma based one-dimensional defective photonic crystal

Abstract

In this work, we analyze the reflectance property of a MCP based 1DPC with symmetrically introduced defect layer of air. The reflectance spectra of the defective PC are obtained by employing TMM with variation in the thickness of the defect. It is reported that the PC with the defect thickness of zero having the form, (AB)N/2(BA)N/2, exhibits two adjacent completely reflected bands separated by a defect mode with reflectance zero. The conventional extrinsic PC offers a single completely reflected band lying in the range 4–6 GHz that splits into two parts by defect mode when we operate the PC in defective mode. By increasing the defect thickness up to 15 mm, the low frequency band becomes narrower and the defect mode frequency is shifted towards a lower value, whereas the second band becomes wider. The defect mode frequency shows a similar decreasing behavior with increase in the thickness of air defect below and above its particular value of 20 mm. In this investigation, the disappearance of defect mode at a critical thickness and reappearance of new defect mode at higher frequency with further increase in defect thickness, are considered as important features of this defective PC. Such kind of tunability in the reflected band, defect mode frequency, and reappearance of new defect mode, all are in a good agreement with the computed results reported by the researchers. The insights of the analysis can be employed in design of optical filters, waveguides, detectors, and similar tunable microwave and switching devices.