Extraordinary characteristics for one-dimensional parity-time-symmetric periodic ring optical waveguide networks

Abstract

In this paper, we design a one-dimensional (1D) parity-time-symmetric periodic ring optical waveguide network (PTSPROWN) and investigate its extraordinary optical characteristics. It is found that quite different from traditional vacuum/dielectric optical waveguide networks, 1D PTSPROWN cannot produce a photonic ordinary propagation mode, but can generate simultaneously two kinds of photonic nonpropagation modes: attenuation propagation mode and gain propagation mode. It creates neither passband nor stopband and possesses no photonic band structure. This makes 1D PTSPROWN possess richer spontaneous PT-symmetric breaking points and causes interesting extremum spontaneous PT-symmetric breaking points to appear, where electromagnetic waves can create ultrastrong extraordinary transmission, reflection, and localization, and the maximum can arrive at 6.6556 × 10 12 and is more than 7 orders of magnitude larger than the results reported previously. 1D PTSPROWN may possess potential in designing high-efficiency optical energy saver devices, optical amplifiers, optical switches with ultrahigh monochromaticity, and so on.

The Scattering Problem in PT‐Symmetric Periodic Structures of 1D Two‐Material Waveguide Networks

“…We call Equation the network equation for the 1D two‐material waveguide network. One can calculate the transmissivity, reflectivity, and photonic localization in our model using the network equation with the generalized eigenfunction method.…”

Quasi‐Blackbody, Bidirectional Super Reflection, and New Total Reflection Produced by Periodic Optical Waveguide Networks Based on Three‐Order PT‐Symmetric Substructures

“…[ 5 ] constructed PT‐symmetric optical systems with complex refractive index materials under paraxial approximation condition, which followed $$n(x)=n^{*}(x)$$ distribution. Subsequently, the special optical characteristics of PT‐symmetric optical systems, [ 5–25 ] such as unidirectional invisibility, [ 10–16,20,22 ] ultrastrong transmission and reflection, [ 11,15,19 ] and coherent perfect absorption, [ 8,16,21 ] have attracted widespread attention. In, 2017, our research group [ 18 ] combined the concept of PT‐symmetry with optical waveguide networks to construct PT‐symmetric optical waveguide networks.…”

“…Then, the singular optical properties of EM waves when propagating in these networks were studied, such as photon modes, ultrastrong extraordinary transmission and reflection, and photonic band gap. Further research [19][20][21][22][23] showed that when EM waves propagate in networks with different PT-symmetric substructures, the singular features are significantly different from each other. Identifying the causes for these differences is an interesting problem in the study of PT-symmetry systems.…”

Extraordinary propagation characteristics of electromagnetic waves in one-dimensional anti-PT-symmetric ring optical waveguide network*

“…This artificial optical system has also aroused great interest [15][16][17][18][19][20] due to several extraordinary phenomena such as flat broadband light transport, [16] chiral mode conversion, [17] and ultra-strong transmission and reflection, [18] non-Hermitian particle-hole symmetry, [15,19] coherent switch. [20] In 1998, optical waveguide networks [21][22][23][24][25][26][27][28][29][30][31][32][33][34] were proposed as a new kind of photonic bandgap (PBG) structure. Compared with photonic crystals, it exhibits excellent characteristics such as higher flexibility in structural symmetry, [21,23,24] and great convenience in measuring the phase and amplitude of EM waves.…”

“…[21,23] Consequently, several interesting optical features and phenomena have been demonstrated in waveguide networks, such as extremely wide PBG, [24,25] comb-like optical transmission spectrum, [27,28] and ultra-strong photonic localization. [32,33] So far, there has been no report that involves a combination of optical waveguide network and anti-PT symmetry. The PT -symmetric optical waveguide network is composed of ma-terials whose imaginary parts of refractive indices are positive and negative simultaneously.…”