Planar Bilayer PT-Symmetric Systems and Resonance Energy Transfer

Parity-time (PT) symmetry provides an outstanding improvement of photonic devices' performance due to the remarkable physics behind it. Resonance energy transfer (RET) as an important characteristic mediating the molecules that can be tailored in the PT-symmetric environment, too. We study how planar bilayer PT-symmetric systems affect the process of resonance energy transfer occurring in the vicinity thereof. First, we investigate the reflectance and transmittance spectra of such systems by calculating reflection and transmission coefficients as well as total radiation amplification as functions of medium parameters. We obtain that reflectance and total amplification are greatest near the exceptional points of the PT-symmetric system. Then, we perform numerical calculations of the RET rate and investigate its dependence on the complex permittivity of the PT-symmetric medium, dipole orientation, frequency of radiation and layer thickness. Optically thick PT-symmetric systems may operate at lower gain at the expense of the appearance of chaotic-like behaviors. These appear owing to the dense oscillations in the reflectance and transmittance spectra and vividly manifest themselves as stochastic-like positions of the exceptional points for PT-symmetric bilayers. The RET rate, being a result of the field interference, can be significantly amplified and suppressed near exceptional points exhibiting a Fano-like lineshape.