Magneto-optic effect on the pole of the parity-time symmetric coupled cavities

Abstract

We propose a compound structure constructed by two magnetic cavities with parity-time (PT) symmetric configuration. Through the calculations based on transfer matrix, we find that the structure system has some unique properties that the usual PT symmetric structures do not have. The four incident conditions of the structure produce two sets of transmittance spectra and four different reflectance spectra in which the unusual amplification and absorption are shown. The huge amplification and absorption can be precisely tuned through the magnetic field. Furthermore, the amplification and absorption around the pole can be reversed through the change of incidence directions. Although the analysis of the scattering matrix shows that the transmission and reflection are not nonreciprocal, the diverse modulation ways (magnetic field and incidence directions) will make the structure more useful in the design of photonic switching and optical modulator.