Coherent Perfect Absorbers: Time-reversed Lasers

Chong, Yidong; Li, Ge; Cao, Hui; Stone, A. Douglas

doi:10.1364/qels.2010.qpda5

Cited by 78 publications

(140 citation statements)

References 5 publications

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“…In the broken phase (red curve), the second components of the eigenvectors are purely imaginary, and under conjugation, one of the components transforms into the other. It should be pointed out that the unusual scattering properties of the PT -symmetric medium have also been demonstrated in optics and electronics, both in theories and experiments [41,42,44,45].…”

Section: Scattering Propertiesmentioning

confidence: 94%

PT-Symmetric Acoustics

et al. 2014

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We introduce here the concept of acoustic parity-time (PT ) symmetry and demonstrate the extraordinary scattering characteristics of the acoustic PT medium. On the basis of exact calculations, we show how an acoustic PT -symmetric medium can become unidirectionally transparent at given frequencies. Combining such a PT -symmetric medium with transformation acoustics, we design two-dimensional symmetric acoustic cloaks that are unidirectionally invisible in a prescribed direction. Our results open new possibilities for designing functional acoustic devices with directional responses.

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Section: Scattering Propertiesmentioning

confidence: 94%

PT-Symmetric Acoustics

et al. 2014

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“…Numerous intriguing optical phenomena have been observed in optical P T -symmetric systems, such as P T -symmetry phase transition and exceptional points [5][6][7][8], unidirectional invisibility [9,10], etc. Especially, an optical P T -symmetric medium can simultaneously behave as a coherent perfect absorber with 100% absorption [11][12][13][14], and as a laser oscillator [15,16] by simply adjusting the amplitudes and phases of incoming waves. Such a unique device is denoted as a CPA laser [17,18].…”

Section: Introductionmentioning

confidence: 99%

Simultaneous realization of a coherent perfect absorber and laser by zero-index media with both gain and loss

et al. 2016

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We investigate a unique type of zero-index medium with both gain and loss (ZIMGL), whose effective permittivity and permeability are both purely imaginary but of opposite signs. We analytically show that, by using a slab of ZIMGL with equal magnitude of loss and gain, simulation realization of a coherent perfect absorber (CPA) and laser, i.e., the so-called CPA laser, can be achieved. Previously the CPA laser was proposed in parity-time (P T ) symmetric systems. However, the ZIMGL does not possess the P T symmetry and thus the underlying physics is distinctly different. By designing a photonic crystal (PC) composed of core-shell rods, with loss and gain distributed in either the core or the shell, we have realized such a ZIMGL. The CPA-laser functionality of such a PC is also confirmed in our numerical simulations. Our work provides a different approach for simultaneous realization of CPA and laser besides P T -symmetric systems.

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“…Such non-Hermitian potential regions 4,5 , which serve as sources and sinks for waves, respectively, can give rise to novel wave effects that are impossible to realize with conventional, Hermitian potentials. Examples of this kind, which were meanwhile also realized in the experiment [6][7][8][9][10] , are the unidirectional invisibility of a gain-loss potential 11 , devices that can simultaneously act as laser and as a perfect absorber [12][13][14] and resonant structures with unusual features like non-reciprocal light transmission 10 or loss-induced lasing [15][16][17] . In particular, systems with a so-called parity-time (PT ) symmetry 18 , where gain and loss are carefully balanced, have recently attracted enormous interest in the context of nonHermitian photonics [19][20][21][22][23][24] .…”

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confidence: 99%

Constant-intensity waves and their modulation instability in non-Hermitian potentials

et al. 2015

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In all of the diverse areas of science where waves play an important role, one of the most fundamental solutions of the corresponding wave equation is a stationary wave with constant intensity. The most familiar example is that of a plane wave propagating in free space. In the presence of any Hermitian potential, a wave's constant intensity is, however, immediately destroyed due to scattering. Here we show that this fundamental restriction is conveniently lifted when working with non-Hermitian potentials. In particular, we present a whole class of waves that have constant intensity in the presence of linear as well as of nonlinear inhomogeneous media with gain and loss. These solutions allow us to study the fundamental phenomenon of modulation instability in an inhomogeneous environment. Our results pose a new challenge for the experiments on non-Hermitian scattering that have recently been put forward.

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Coherent Perfect Absorbers: Time-reversed Lasers

Cited by 78 publications

References 5 publications

PT-Symmetric Acoustics

PT-Symmetric Acoustics

Simultaneous realization of a coherent perfect absorber and laser by zero-index media with both gain and loss

Constant-intensity waves and their modulation instability in non-Hermitian potentials

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