Transmission-reflection decoupling of non-Hermitian photonic doping epsilon-near-zero media

We present a novel method to achieve the decoupling between the transmission and reflection waves of non-Hermitian doped epsilon-near-zero (ENZ) media by inserting a dielectric slit into the structure. Our method also allows for independent control over the amplitude and the phase of both the transmission and reflection waves through few dopants, enabling us to achieve various optical effects, such as perfect absorption, high-gain reflection without transmission, reflectionless high-gain transmission and reflectionless total transmission with different phases. By manipulating the permittivity of dopants with extremely low loss or gain, we can realize these effects in the same configuration. We also extend this principle to multi-port doped ENZ structures and design a highly reconfigurable and reflectionless signal distributor and generator that can split, amplify, decay and phase-shift the input signal in any desired way. Our method overcomes limitations of optical manipulation in doped ENZ caused by the interdependent nature of the transmission and reflection, and has potential applications in novel photonic devices.