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.

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 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.

scholarly journals A New Design of a Wideband Miniature Antenna Array

2017 ◽  
Vol 7 (4) ◽  
pp. 1850
Author(s):  
Oulhaj Otman ◽  
Naima A. Touhami ◽  
Mohamed Aghoutane ◽  
Abdelmounaim Belbachir Kchairi
Keyword(s):  
Reflection Coefficient ◽  
Circular Polarization ◽  
Antenna Array ◽  
Frequency Band ◽  
Microstrip Antenna ◽  
Antenna Element ◽  
Wide Frequency Band ◽  
Microstrip Antenna Array ◽  
Miniature Antenna

In this work, we present a new configuration of a new miniature microstrip antenna array having a wide frequency band and with a circular polarization. The bandwidth is about 2GHz for a reflection coefficient under -10dB and centered on the ISM ‘Industrial Scientific Medical’ band at 5.8 GHz. To design such array, we have started the design by validating one antenna element at 10 GHz and after that by using the technique of defected ground, we have validated the antenna array in the frequency band [4 GHz -6 GHz] which will permit to miniature the dimensions. The final fabricated antenna array is mounted on an FR4 substrate, the whole area is 102.48 X 31.39 mm<sup>2</sup>  with a gain of 5dBi at 4GHz.

NO, CO and H2S based pharmaceuticals in the mission of vision (eye health): a comprehensive review

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jan Mohammad Mir ◽  
Ram Charitra Maurya ◽  
Mohd Washid Khan
Keyword(s):  
Nitric Oxide ◽  
Carbon Monoxide ◽  
Human Physiology ◽  
Hydrogen Sulfide ◽  
The Other ◽  
Normal Functioning ◽  
Comprehensive Review ◽  
Molecular Systems ◽  
Eye Health ◽  
Highly Sensitive

Abstract A set of well defined signaling molecules responsible for normal functioning of human physiology including nitric oxide along with carbon monoxide and hydrogen sulphide are referred as “gasotransmitters”. Due to their involvement in almost every system of a human body, the care of highly sensitive organs using these molecules as drugs represents highly fascinating area of research. In connection with these interesting aspects, the applied aspects of these gaseous molecules in maintaining healthy eye and vision have been targeted in this review. Several examples of eye-droppers including NORMs like latanoprost and nipradiol, CORMs like CORM-3 and CORM-A1, and Hydrogen sulfide releasing system like GYY4137 have been discussed in this context. Therefore the relation of these trio-gasotransmitters with the ophthalmic homeostasis on one hand, and de-infecting role on the other hand has been mainly highlighted. Some molecular systems capable of mimicking gasotransmitter action have also been introduced in connection with the titled theme.

THE HORMONAL COMPOSITION OF MILK IN PRODUCTIVE ANIMALS AND ITS SAFETY FOR HUMANS

2020 ◽  
Vol 1 (3) ◽  
pp. 313-321
Author(s):  
P.A. Popov ◽  
◽  
V.S. Babunova ◽  
Keyword(s):  
Trace Elements ◽  
Growth Factor ◽  
Dairy Products ◽  
The Body ◽  
The Other ◽  
Raw Material ◽  
Important Food ◽  
The Past ◽  
Highly Sensitive ◽  
And Control

Hormones are an integral part of milk and throughout lactation, the content of certain hormones is unstable. Hormones regulate the process of starting lactation of animals, the lactation process itself, and also the other functions of the body. Milk is of great importance for the growth of young animals and the formation of immunity. Milk is a special product in the diet and is an important food and raw material for the production of dairy products for people. It contains a large amount of protein, fat, carbohydrates, vitamins and trace elements in biologically available form. But at the same time, over the past few years, more and more evidence has emerged that hormones in dairy products can impact on human health. Thus, some estrogens and insulin-like growth factor IGF-1 are involved in the initiation and provocation of breast, prostate and endometrial tumors. That’s why, it is necessary to normalize and control the content of certain hormones in milk with highly sensitive methods.

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