Transmission through a one-dimensional photonic lattice modulated by the side-coupled PT-symmetric non-Hermitian Su-Schrieffer-Heeger chain

We theoretically study the quantum transmission through a one-dimensional photonic lattice that couples laterally to the one parity-time (PT)-symmetric non-Hermitian Su-Schrieffer-Heeger (SSH) chain. It is found that the SSH chain plays important roles in modifying the transmission properties of this system. In the case of weak coupling, the effect of the SSH chain is manifested mainly as the antiresonance caused by the edge states when it is in a topologically nontrivial region. And when the PT -symmetric complex potentials are introduced at the ends of the SSH chain, the edge states undergo PT -symmetry breaking accompanied by a notable change in transmission function spectra. On the other hand, few changes can be observed in the topologically trivial region of the SSH chain. For the strong coupling case, the antiresonance effect of the non-Hermitian SSH chain is apparently modified. Our findings provide helpful content for describing the physics properties of the PT -symmetric non-HermitianSSHchain. (C) 2021 Optical Society of America