Non-Hermitian physics and PT symmetry

El‐Ganainy, Ramy; Makris, Konstantinos G.; Khajavikhan, Mercedeh; Musslimani, Ziad H.; Rotter, Stefan; Christodoulides, Demetrios N.

doi:10.1038/nphys4323

Cited by 2,179 publications

(1,441 citation statements)

References 119 publications

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“…PT -symmetric structures and PT symmetry breaking seem to be one of the most intensively studied fields in optics and photonics of active systems [1][2][3]. It dates back to the seminal works of Bender and Boettcher [4,5], who discovered the real-valued spectra of non-Hermitian Hamiltonians in quantum mechanics, provided these Hamiltonians are parity-time (PT ) symmetric, i.e., invariant with respect to simultaneous parity change and time reversal.…”

Section: Introductionmentioning

confidence: 99%

PT symmetry breaking in multilayers with resonant loss and gain locks light propagation direction

et al. 2018

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Using the Maxwell-Bloch equations for resonantly absorbing and amplifying media, we study the temporal dynamics of light propagation through the PT -symmetric structures with alternating loss and gain layers. This approach allows us to precisely describe the response of the structure near the exceptional points of PT -symmetry breaking phase transition and, in particular, take into account the nonlinear effect of loss and gain saturation in the PT -symmetry broken state. We reveal that in this latter state the multilayer system possesses a lasing-like behavior releasing the pumped energy in the form of powerful pulses. We predict locking of pulse direction due to the PT -symmetry breaking, as well as saturation-induced irreversibility of phase transition and nonreciprocal transmission.

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Section: Introductionmentioning

confidence: 99%

PT symmetry breaking in multilayers with resonant loss and gain locks light propagation direction

et al. 2018

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“…Infrared stealth technology has been widely used in field of spacecraft components [1], camouflage platforms [2], protective clothing [3], container packaging [4], and so on [5–7]. Especially to the military security and military surveillance field, which can protect the aircraft from detection.…”

Section: Introductionmentioning

confidence: 99%

Highly Stretchable Micro/Nano Wrinkle Structures for Infrared Stealth Application

Wang

Cui

et al. 2018

Nanoscale Res Lett

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We demonstrate a novel infrared stealth structure consisting of SiO2/TiO2 film, which was manufactured as the highly stretchable triangular wrinkle structures. The triangular wrinkle structures have firstly been transferred to the flexible substrate from the surface of Si-substrate, which was manufactured by the MEMS technology. Then, the infrared reflective film have been manufactured to be the triangular wrinkle structures by depositing the materials (noble metal (Ag or Au) or multilayer oxide (SiO2/TiO2)) on the surface of flexible substrate. Due to the lower reflection effect of curved surface, the infrared reflectivity of these structures has been tuned down to 5%. And, compared to the flat surface, the reflection-to-diffuse ratios improved approximately one order of magnitude. These structures can adapt to the environment by changing the reflectivity of triangular wrinkle structures under stretching. Finally, an Au-modified infrared stealth structure has been fabricated as the array structures, which disappeared and then display by stretching the triangular wrinkle structures at room temperature. It features high reflection-to-diffuse ratios, stable repeatability, low-cost, and easy to manufacture. It may open opportunities for infrared camouflage for military security and surveillance field application.

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“…The study of state-dependent channels in wave systems is readily found in traditional photonic devices, such as laser with gain saturation [12] and mode locking [13] with saturable absorption. [17] Non-Hermitian photonics [18][19][20] inspired by parity-time (PT) symmetry [21] has rejuvenated the utilization of nonlinear wave channels for photonic [22][23][24] or microwave [25] functionalities. [17] Non-Hermitian photonics [18][19][20] inspired by parity-time (PT) symmetry [21] has rejuvenated the utilization of nonlinear wave channels for photonic [22][23][24] or microwave [25] functionalities.…”

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confidence: 99%

Neuromorphic Functions of Light in Parity‐Time‐Symmetric Systems

Piao

Park

2019

Advanced Science

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As an elementary processor of neural networks, a neuron performs exotic dynamic functions, such as bifurcation, repetitive firing, and oscillation quenching. To achieve ultrafast neuromorphic signal processing, the realization of photonic equivalents to neuronal dynamic functions has attracted considerable attention. However, despite the nonconservative nature of neurons due to energy exchange between intra‐ and extra‐cellular regions through ion channels, the critical role of non‐Hermitian physics in the photonic analogy of a neuron has been neglected. Here, a neuromorphic non‐Hermitian photonic system ruled by parity‐time symmetry is presented. For a photonic platform that induces the competition between saturable gain and loss channels, dynamical phases are classified with respect to parity‐time symmetry and stability. In each phase, unique oscillation quenching functions and nonreciprocal oscillations of light fields are revealed as photonic equivalents of neuronal dynamic functions. The proposed photonic system for neuronal functionalities will become a fundamental building block for light‐based neural signal processing.

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Non-Hermitian physics and PT symmetry

Cited by 2,179 publications

References 119 publications

PT symmetry breaking in multilayers with resonant loss and gain locks light propagation direction

PT symmetry breaking in multilayers with resonant loss and gain locks light propagation direction

Highly Stretchable Micro/Nano Wrinkle Structures for Infrared Stealth Application

Neuromorphic Functions of Light in Parity‐Time‐Symmetric Systems

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