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.

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.

scholarly journals Reflection Enhancement and Giant Lateral Shift in Defective Photonic Crystals with Graphene

2019 ◽  
Vol 9 (10) ◽  
pp. 2141 ◽  
Author(s):  
Dong Zhao ◽  
Fangmei Liu ◽  
Peng Meng ◽  
Jie Wen ◽  
Siliu Xu ◽  
...  
Keyword(s):  
Photonic Crystals ◽  
Interband Transition ◽  
Single Layer ◽  
Defect Layer ◽  
Lateral Shift ◽  
Single Layer Graphene ◽  
Intraband Transition ◽  
Highly Sensitive ◽  
Highly Sensitive Sensors ◽  
Periodic Number

This study investigates the reflectance of the defective mode (DM) and the lateral shift of reflected beam in defective photonic crystals incorporated with single-layer graphene by the transfer matrix method (TMM). Graphene, treated as an equivalent dielectric with a thickness of 0.34 nm, was embedded in the center of a defect layer. The reflectance of the DM was greatly enhanced as the intraband transition of electrons was converted to an interband transition in graphene. The reflectance of the DM could be further enhanced by increasing the Bragg periodic number. Furthermore, a large lateral shift of the reflected beam could also be induced around the DM. This study may find great applications in highly sensitive sensors.

scholarly journals Unidirectional Invisibility Induced by Complex Anti-Parity–Time Symmetric Periodic Lattices

2019 ◽  
Vol 9 (18) ◽  
pp. 3808 ◽  
Author(s):  
Hui Cao ◽  
Dong Zhao ◽  
Ming Fang ◽  
Huang Guo ◽  
Yonghong Hu ◽  
...  
Keyword(s):  
Reflection Coefficient ◽  
Parameter Space ◽  
Frequency Band ◽  
Angular Frequency ◽  
Lateral Shift ◽  
The Other ◽  
Wide Frequency Band ◽  
Highly Sensitive ◽  
Highly Sensitive Sensors

Complex anti-parity-time symmetric periodic lattices, in a wide frequency band, can act as unidirectional invisible media. The reflection from one end is suppressed while it is enhanced from the other. Furthermore, unidirectional laser points (ULPs) which correspond to the poles of reflection from one end, arise in the parameter space composed of the permittivity and angular frequency. The phase of the reflection coefficient changes sharply near the ULPs. Subsequently, large lateral shift which is proportional to the slope of phase could be induced for the reflected beam. The study may find great applications in unidirectional invisibility, unidirectional lasers and highly sensitive sensors.

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 Interferometric control of magnon-induced nearly perfect absorption in cavity magnonics

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
J. W. Rao ◽  
P. C. Xu ◽  
Y. S. Gui ◽  
Y. P. Wang ◽  
Y. Yang ◽  
...  
Keyword(s):  
Electromagnetic Waves ◽  
Molecular Detection ◽  
Coupled System ◽  
Critical Coupling ◽  
Perfect Absorption ◽  
Reflection And Transmission ◽  
Single Beam ◽  
Coherent Perfect Absorption ◽  
Channel Interference ◽  
On Chip

AbstractThe perfect absorption of electromagnetic waves has promoted many applications, including photovoltaics, radar cloaking, and molecular detection. Unlike conventional methods of critical coupling that require asymmetric boundaries or coherent perfect absorption that require multiple coherent incident beams, here we demonstrate single-beam perfect absorption in an on-chip cavity magnonic device without breaking its boundary symmetry. By exploiting magnon-mediated interference between two internal channels, both reflection and transmission of our device can be suppressed to zero, resulting in magnon-induced nearly perfect absorption (MIPA). Such interference can be tuned by the strength and direction of an external magnetic field, thus showing versatile controllability. Furthermore, the same multi-channel interference responsible for MIPA also produces level attraction (LA)-like hybridization between a cavity magnon polariton mode and a cavity photon mode, demonstrating that LA-like hybridization can be surprisingly realized in a coherently coupled system.

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

Single Defect in Finite one Dimensional Photonic Crystals

2012 ◽  
Vol 614-615 ◽  
pp. 1629-1632
Author(s):  
Gang Xu ◽  
Yun Sun
Keyword(s):  
Photonic Crystals ◽  
Transmission Coefficient ◽  
Transfer Matrix Method ◽  
Matrix Method ◽  
Defect Mode ◽  
Transmission Peak ◽  
Reflection And Transmission ◽  
One Dimensional ◽  
Single Defect ◽  
Reflection And Transmission Coefficient

Applying transfer matrix method, we get reflection and transmission coefficient of finite one dimensional photonic crystals. At the same time, we consider the position influence of single defect. We find the frequency of defect mode is same, but the height of transmission peak is not same when single defect is in different position of crystal. The transmission peak is maximum when the defect is in center of finite one dimensional photonic crystals.

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