scholarly journals Asymmetric Perfect Absorption and Lasing of Nonlinear Waves by a Complex δ-Potential

Symmetry ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 1675
Author(s):  
Dmitry A. Zezyulin ◽  
Vladimir V. Konotop
Keyword(s):  
Asymptotic Behavior ◽  
Nonlinear Waves ◽  
Stability Of Solutions ◽  
Constant Amplitude ◽  
Perfect Absorption ◽  
Nonlinear Waveguide ◽  
Linear Waves ◽  
Coherent Perfect Absorption ◽  
The Stability ◽  
Linear Counterpart

Spectral singularities and coherent perfect absorption are two interrelated concepts that have originally been introduced and studied for linear waves interacting with complex potentials. In the meantime, the distinctive asymptotic behavior of perfectly absorbed waves suggests considering possible generalizations of these phenomena for nonlinear waves. Here, we address the perfect absorption of nonlinear waves by an idealized infinitely narrow dissipative potential modeled by a Dirac δ-function with an imaginary amplitude. Our main result is the existence of perfectly absorbed flows whose spatial amplitude distributions are asymmetric with respect to the position of the absorber. These asymmetric states do not have a linear counterpart. Their linear stability is verified numerically. The nonlinear waveguide also supports symmetric and constant-amplitude perfectly absorbed flows. The stability of solutions of the latter type can be confirmed analytically.

A FOURTH-ORDER ACCURATE SCHEME FOR SOLVING ONE-DIMENSIONAL HIGHLY NONLINEAR STANDING WAVE EQUATION IN DIFFERENT THERMOVISCOUS FLUIDS

2008 ◽  
Vol 16 (04) ◽  
pp. 563-576 ◽  
Author(s):  
MAJID NABAVI ◽  
M. H. KAMRAN SIDDIQUI ◽  
JAVAD DARGAHI
Keyword(s):  
Standing Wave ◽  
Particle Velocity ◽  
Fourth Order ◽  
Nonlinear Waves ◽  
Numerical Scheme ◽  
Excitation Amplitude ◽  
Time And Space ◽  
Linear Waves ◽  
Highly Nonlinear ◽  
The Stability

Combination of a fourth-order Padé compact finite difference discretization in space and a fourth-order Runge–Kutta time stepping scheme is shown to yield an effective method for solving highly nonlinear standing waves in a thermoviscous medium. This accurate and fast-solver numerical scheme can predict the pressure, particle velocity, and density along the standing wave resonator filled with a thermoviscous fluid from linear to strongly nonlinear levels of the excitation amplitude. The stability analysis is performed to determine the stability region of the scheme. Beside the fourth-order accuracy in both time and space, another advantage of the given numerical scheme is that no additional attenuation is required to get numerical stability. As it is well known, the results show that the pressure and particle velocity waveforms for highly nonlinear waves are significantly different from that of the linear waves, in both time and space. For highly nonlinear waves, the results also indicate the presence of a wavefront that travels along the resonator with very high pressure and velocity gradients. Two gases, air and CO 2, are considered. It is observed that the slopes of the traveling velocity and pressure gradients are higher for CO 2 than those for air. For highly nonlinear waves, the results also indicate the higher asymmetry in pressure for CO 2 than that for air.

scholarly journals Implicit nonlinear fractional differential equations of variable order

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Amar Benkerrouche ◽  
Mohammed Said Souid ◽  
Kanokwan Sitthithakerngkiet ◽  
Ali Hakem
Keyword(s):  
Differential Equations ◽  
Boundary Value Problem ◽  
Fractional Differential Equations ◽  
Boundary Value ◽  
Variable Order ◽  
Stability Of Solutions ◽  
Nonlinear Fractional Differential Equations ◽  
Caputo Fractional Differential Equations ◽  
Fractional Differential ◽  
The Stability

AbstractIn this manuscript, we examine both the existence and the stability of solutions to the implicit boundary value problem of Caputo fractional differential equations of variable order. We construct an example to illustrate the validity of the observed results.

Organic Sub-Bandgap Schottky Barrier Photodetectors with Near-Infrared Coherent Perfect Absorption

ACS Photonics ◽  
2021 ◽  
Author(s):  
Yeonghoon Jin ◽  
Hyung Suk Kim ◽  
Junghoon Park ◽  
Seunghyup Yoo ◽  
Kyoungsik Yu
Keyword(s):  
Schottky Barrier ◽  
Near Infrared ◽  
Perfect Absorption ◽  
Coherent Perfect Absorption

scholarly journals Driving plasmonic nanoantennas at perfect impedance matching using generalized coherent perfect absorption

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Philipp Grimm ◽  
Gary Razinskas ◽  
Jer-Shing Huang ◽  
Bert Hecht
Keyword(s):  
Impedance Matching ◽  
Plasmonic Waveguide ◽  
Perfect Absorption ◽  
Single Nanowire ◽  
Coherent Perfect Absorption ◽  
Potential Applications ◽  
Plasmonic Nanoantennas ◽  
Radiative Losses ◽  
Additional Loss

Abstract Coherent perfect absorption (CPA) describes the absence of all outgoing modes from a lossy resonator, driven by lossless incoming modes. Here, we show that for nanoresonators that also exhibit radiative losses, e.g., plasmonic nanoantennas, a generalized version of CPA (gCPA) can be applied. In gCPA outgoing modes are suppressed only for a subset of (guided plasmonic) modes while other (radiative) modes are treated as additional loss channels - a situation typically referred to as perfect impedance matching. Here we make use of gCPA to show how to achieve perfect impedance matching between a single nanowire plasmonic waveguide and a plasmonic nanoantenna. Antennas with both radiant and subradiant characteristics are considered. We further demonstrate potential applications in background-free sensing.

Tunable coherent perfect absorption in three-dimensional Dirac semimetal films

2021 ◽  
Vol 19 (8) ◽  
pp. 081601
Author(s):  
Jipeng Wu ◽  
Jie Tang ◽  
Rongzhou Zeng ◽  
Xiaoyu Dai ◽  
Yuanjiang Xiang
Keyword(s):  
Three Dimensional ◽  
Perfect Absorption ◽  
Dirac Semimetal ◽  
Coherent Perfect Absorption

An electromagnetic perspective of coherent perfect absorption

2018 ◽  
Vol 94 (1) ◽  
pp. 015502
Author(s):  
Sanjeeb Dey ◽  
Suneel Singh
Keyword(s):  
Perfect Absorption ◽  
Coherent Perfect Absorption
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