2021/07/22 by Tahere Hemati, Yi Zou, Hemati, Tahere +3
Physics and Astronomy · #Advanced Fiber Laser Technologies #FOS: Physical sciences #Nonlinear Photonic Systems #Optics (physics.optics) #Quantum Mechanics and Non-Hermitian Physics
paper · pdf · doi:10.48550/arxiv.2107.10921
openalex publication_date 2021/07/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
This work presents a theoretical investigation of an active photonic grating of the parity-time (PT) symmetric architecture. The analytical study of the free-space mode propagation from the grating structure indicates the unique bifurcation property due to the PT-symmetry modulation. It is shown that both the gain/loss contrast and the lattice constant parameters are critical factors to modulate the active photonic system in between the PT-symmetry to the symmetry-broken phases. Furthermore, numerical simulations via the Rigorous Coupled-Wave Analysis (RCWA) method discover the existence of a unique Spectral Singularity (SS) phenomenon in this PT grating structure, which corresponds to a non-trivial single-mode and near-zero bandwidth photonic resonant emission. Also, the guiding procedure for fulfilling SS modes is found to be related to the unique formation of the scattering matrix applied in the PT-symmetric photonic gratings. This theoretical work takes a fresh look into the active PT-symmetric photonic gratings focusing on the discovery of new free-space emission modes rather than the commonly studied unidirectional properties, which could contribute to the development of novel low-threshold and super-coherent surface-emitting devices.