Microwave Tunneling and Robust Information Transfer Based on Parity-Time-Symmetric Absorber-Emitter Pairs

Abstract

<jats:p>Robust signal transfer in the form of electromagnetic waves is of fundamental importance in modern technology, yet its operation is often challenged by unwanted modifications of the channel connecting transmitter and receiver. Parity-time- (PT-) symmetric systems, combining active and passive elements in a balanced form, provide an interesting route in this context. Here, we demonstrate a PT-symmetric microwave system operating in the extreme case in which the channel is shorted through a small reactance, which acts as a nearly impenetrable obstacle, and it is therefore expected to induce large reflections and poor transmission. After placing a gain element behind the obstacle, and a balanced lossy element in front of it, we observe full restoration of information and overall transparency to an external observer, despite the presence of the obstacle. Our theory, simulations, and experiments unambiguously demonstrate stable and robust wave tunneling and information transfer supported by PT symmetry, opening opportunities for efficient communication through channels with dynamic changes, active filtering, and active metamaterial technology.</jats:p>

Topological Metamaterials

“…EPs are of great interest for various applications. EPs enable unidirectional light transport, leading to the observation of anisotropic transmission resonances, ,,, and directional power flow in microlaser cavities. − The accidental coalescence of eigenmodes offers rich topological features, enabling dynamic chiral-mode conversion, ,, and advanced optical sensing. ,,− scriptP scriptT -symmetric systems hold great promise for imaging, ,− lasing, cloaking and transformation optics, , new mechanisms of wave transport, − topology, light scattering engineering, ,, and wireless power transfer. ,, …”

“…548,549,1195−1197 -symmetric systems hold great promise for imaging, 705,1198−1202 lasing, 1184 cloaking and transformation optics, 1203,1204 new mechanisms of wave transport, 1205−1207 topology, 1208 light scattering engineering, 543,1209,1210 and wireless power transfer. 1171,1211,1212 -symmetric systems also exhibit various intriguing topological properties. For instance, in a Hermitian system featuring a Dirac cone, the introduction of balanced gain and loss can cause both cones to move inside one another, forming an exceptional ring in reciprocal space.…”

Low-Symmetry Nanophotonics

“…), the system is in the tight coupling mode, when the coherent exchange of energy between the elements compensates for the dissipation, stabilizing the system on the real frequency axis. The critical point The abrupt phase transition at EPs enables a number of intriguing phenomena, including enhanced sensing [271][272][273][274][275][276][277][278][279][280][281] , exotic lasing 268,[282][283][284] , optical isolation and nonreciprocity [285][286][287][288] , loss-induced transparency 289 , unidirectional invisibility 243,[290][291][292] , robust wireless power transfer 267,293 , and topological chirality 261,294 . PT-symmetry requires a balance between loss and gain, which is difficult to achieve in experiments, especially at a higher frequency.…”

“…The abrupt phase transition at EPs enables a number of intriguing phenomena, including enhanced sensing, − exotic lasing, ,− optical isolation and nonreciprocity, − loss-induced transparency, unidirectional invisibility, ,− robust wireless power transfer, , and topological chirality. , PT symmetry requires a balance between loss and gain, which is difficult to achieve in experiments, especially at a higher frequency. However, some interesting physical aspects of PT symmetry can also be investigated in non-Hermitian loss-shifted systems and loss-only structures.…”

Erratum to “Microwave Tunneling and Robust Information Transfer Based on Parity-Time-Symmetric Absorber-Emitter Pairs”

“…In the article titled "Microwave Tunneling and Robust Information Transfer Based on Parity-Time-Symmetric Absorber-Emitter Pairs" [1], there were errors in Figure 2 which occurred during production. In panel (c), the red line should be attributed to "Re (ZNIC/Z0)" and the blue line should be attributed to "Im (ZNIC/Z0)."…”