scholarly journals Near-perfect absorption by photonic crystals with a broadband and omnidirectional impedance-matching property

2019 ◽  
Vol 27 (11) ◽  
pp. 15800 ◽  
Author(s):  
Jie Luo ◽  
Yun Lai
Keyword(s):  
Photonic Crystals ◽  
Impedance Matching ◽  
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.

scholarly journals Numerical Study of an Ultra-Broadband All-Silicon Terahertz Absorber

2020 ◽  
Vol 10 (2) ◽  
pp. 436 ◽  
Author(s):  
Jinfeng Wang ◽  
Tingting Lang ◽  
Tingting Shen ◽  
Changyu Shen ◽  
Zhi Hong ◽  
...  
Keyword(s):  
Numerical Study ◽  
Structural Parameters ◽  
Impedance Matching ◽  
Single Layer ◽  
Transverse Magnetic ◽  
Absorption Efficiency ◽  
Absorption Mechanism ◽  
Loss Mechanism ◽  
Perfect Absorption ◽  
Terahertz Absorber

In this article we present and numerically investigate a broadband all-silicon terahertz (THz) absorber which consists of a single-layer periodic array of a diamond metamaterial layer placed on a silicon substrate. We simulated the absorption spectra of the absorber under different structural parameters using the commercial software Lumerical FDTD solutions, and analyzed the absorption mechanism from the distribution of the electromagnetic fields. Finally, the absorption for both transverse electric (TE) and transverse magnetic (TM) polarizations under different incident angles from 0 to 70° were investigated. Herein, electric and magnetic resonances are proposed that result in perfect broadband absorption. When the absorber meets the impedance matching principle in accordance with the loss mechanism, it can achieve a nearly perfect absorption response. The diamond absorber exhibits an absorption of ~100% at 1 THz and achieves an absorption efficiency >90% within a bandwidth of 1.3 THz. In addition, owing to the highly structural symmetry, the absorber has a polarization-independent characteristic. Compared with previous metal–dielectric–metal sandwiched absorbers, the all-silicon metamaterial absorbers can avoid the disadvantages of high ohmic losses, low melting points, and high thermal conductivity of the metal, which ensure a promising future for optical applications, including sensors, modulators, and photoelectric detection devices.

Wideband waveguide loading impedance matching on the basis of photonic crystals with nanometer metal layers

2009 ◽  
Vol 52 (1) ◽  
pp. 50-54 ◽  
Author(s):  
D. A. Usanov ◽  
A. V. Skripal ◽  
A. V. Abramov ◽  
A. S. Bogolubov ◽  
V. S. Skvortsov ◽  
...  
Keyword(s):  
Photonic Crystals ◽  
Impedance Matching ◽  
Loading Impedance ◽  
Metal Layers

scholarly journals Observation of wide-angle impedance matching in terahertz photonic crystals

2020 ◽  
Vol 22 (2) ◽  
pp. 023033 ◽  
Author(s):  
Shanshan Li ◽  
Yu Wang ◽  
Wenya Zhang ◽  
Weixin Lu ◽  
Bo Hou ◽  
...  
Keyword(s):  
Photonic Crystals ◽  
Impedance Matching ◽  
Wide Angle

Coherent perfect absorption in the one-dimensional non-magnetized plasma photonic crystals

2021 ◽  
Author(s):  
Fupei Wu ◽  
Hao Zhang ◽  
Baofei Wan ◽  
Haifeng Zhang
Keyword(s):  
Photonic Crystals ◽  
Optical Switching ◽  
Absorption Efficiency ◽  
Magnetized Plasma ◽  
Light Modulation ◽  
Perfect Absorption ◽  
One Dimensional ◽  
Coherent Perfect Absorption ◽  
Plasma Photonic Crystals ◽  
The One

Abstract Electromagnetic (EM) absorption is the basic characteristic of materials that plays an important role in many applications such as solar cells, EM radiation protection, and stealth technology. However, under normal circumstances, the traditional medium's absorption efficiency of EM waves is limited, but the designer can operate by adjusting the structure of the medium. In this paper, the coherent perfect absorption (CPA) is introduced in the one-dimensional (1-D) non-magnetized plasma photonic crystals. Under the premise that the selected material meets the conditions (appropriate thickness and dielectric constant), the absorption amplitude at the frequency point that meets the coherent absorption conditions is greatly improved. The results show that the forward and backward EM waves that meet the CPA conditions and propagate in PPCs can increase the absorption to 99.94% and change the phase difference of the two coherent beams to control the adjustment range of the absorption efficiency to 12.60%-99.94%. In addition, the effects of plasma and collision frequency on the absorption property, and the effects of the periodic constant of dielectric layers and plasma thickness on the frequency and amplitude of coherent absorption are also presented. It is foreseeable that the idea of tunability of light absorption in photovoltaic cells is proposed in this paper, and the application of absorbers in the field of optical switching and light modulation has been further expanded.

scholarly journals Perfect absorption and no reflection in disordered photonic crystals

2017 ◽  
Vol 95 (5) ◽  
Author(s):  
Jin-Hui Wu ◽  
M. Artoni ◽  
G. C. La Rocca
Keyword(s):  
Photonic Crystals ◽  
Perfect Absorption

scholarly journals Broadband impedance modulation via non-local acoustic metamaterials

2021 ◽  
Author(s):  
Zhiling Zhou ◽  
Sibo Huang ◽  
Dongting Li ◽  
Jie Zhu ◽  
Yong Li
Keyword(s):  
Frequency Band ◽  
Linear Time ◽  
Impedance Matching ◽  
Local Effect ◽  
Selective Absorption ◽  
Acoustic Metamaterials ◽  
Perfect Absorption ◽  
Impedance Modulation ◽  
Dual Functional ◽  
Non Local

Abstract Causality of linear time-invariant systems inherently defines the wave-matter interaction process in wave physics. This principle imposes strict constraints on the interfacial response of materials on various physical platforms. A typical consequence is that a delicate balance has to be struck between the conflicting bandwidth and geometric thickness when constructing a medium with desired impedance, which makes it challenging to realize broadband impedance modulation with compact structures. In pursue of improvement, the over-damped recipe and the reduced excessive response recipe are creatively presented in this work. As proof-of-concept demonstration, we construct a metamaterial with intensive mode density which supports strong non-locality over a frequency band from 320 Hz to 6400 Hz. Under the guidelines of the over-damped recipe and the reduced excessive response recipe, the metamaterial realizes impedance matching to air and exhibits broadband near-perfect absorption without evident impedance oscillation and absorption dips in the working frequency band. We further present a dual-functional design capable of frequency-selective absorption and reflection by concentrating the resonance modes in three frequency bands. Our research reveals the significance of the over-damped recipe and the strong non-local effect in broadband impedance modulation, which may open up avenues for constructing efficient artificial impedance boundaries for energy absorption and other wave manipulation.

Perfect absorption of the graphene with truncated photonic crystals

2016 ◽  
Author(s):  
Yiping Liu ◽  
Lei Du ◽  
Guang Lu ◽  
Shan Zhang ◽  
Fen Liu ◽  
...  
Keyword(s):  
Photonic Crystals ◽  
Perfect Absorption

scholarly journals Exceptional Points in Non-Hermitian Photonic Crystals Incorporated With a Defect

2020 ◽  
Vol 10 (3) ◽  
pp. 823 ◽  
Author(s):  
Fangmei Liu ◽  
Dong Zhao ◽  
Hui Cao ◽  
Bin Xu ◽  
Wuxiong Xu ◽  
...  
Keyword(s):  
Reflection Coefficient ◽  
Photonic Crystals ◽  
Perfect Absorption ◽  
Complex Phase ◽  
One Dimensional ◽  
Exceptional Points ◽  
Coherent Perfect Absorption ◽  
Highly Sensitive ◽  
Gain Loss ◽  
Highly Sensitive Sensors

We explored exceptional points (EPs) in one dimensional non-Hermitian photonic crystals incorporated with a defect. The defect was asymmetric with respect to the center. Two EPs could be derived by modulating the normalized frequency and the gain-loss coefficient of defect. The reflection coefficient complex phase changed dramatically around EPs, and the change in complex phase was π at EPs. The electric field of EPs was mainly restricted to the defect, which can induce a giant Goos–Hänchen (GH) shift. Moreover, we found a coherent perfect absorption-laser point (CPA-LP) in the structure. A giant GH shift also existed around the CPA-LP. The study may have found applications in highly sensitive sensors.

Coherent Perfect Absorption Laser Points in One-Dimensional Anti-Parity–Time-Symmetric Photonic Crystals

2019 ◽  
Vol 9 (13) ◽  
pp. 2738 ◽  
Author(s):  
Huiling Wang ◽  
Weihao Kong ◽  
Pu Zhang ◽  
Zhongming Li ◽  
Dong Zhong
Keyword(s):  
Photonic Crystals ◽  
Loss Factor ◽  
Angular Frequency ◽  
Sharp Change ◽  
Perfect Absorption ◽  
Reflection And Transmission ◽  
Coherent Perfect Absorption ◽  
Highly Sensitive ◽  
Gain Loss ◽  
Highly Sensitive Sensors

We investigate the coherent perfect absorption laser points (CPA-LPs) in anti-parity–time-symmetric photonic crystals. CPA-LPs, which correspond to the poles of reflection and transmission, can be found in the parameter space composed of gain–loss factor and angular frequency. Discrete exceptional points (EPs) split as the gain–loss factor increases. The CPA-LPs sandwiched between the EPs are proved to be defective modes. The localization of light field and the bulk effect of gain/loss in materials induce a sharp change in phase of the reflection coefficient near the CPA-LPs. Consequently, a large spatial Goos–Hänchen shift, which is proportional to the slope of phase, can be achieved around the CPA-LPs. The study may find great applications in highly sensitive sensors.

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