LEFT-HANDNESS IN A FOUR-LEVEL ATOMIC SYSTEM

2009 ◽  
Vol 07 (04) ◽  
pp. 747-754 ◽  
Author(s):  
SHUNCAI ZHAO ◽  
ZHENGDONG LIU
Keyword(s):  
Resonance Frequency ◽  
Frequency Band ◽  
Quantum Coherence ◽  
Atomic System ◽  
Negative Permittivity ◽  
Negative Permeability ◽  
Potential Applications

A scheme is proposed for realizing simultaneous negative permittivity and negative permeability based on quantum coherence in a four-level dense atomic system here. Under some parametric conditions the system shows that simultaneous negative permittivity and negative permeability (i.e. Left-handness) can be achieved in a wider frequency band because of quantum coherence. And the novelty properties of gain and dispersion near the resonance frequency may have some potential applications.

scholarly journals Negative Refraction Using Frequency-Tuned Oxide Multilayer Structure

2008 ◽  
Vol 2008 ◽  
pp. 1-4
Author(s):  
Yalin Lu ◽  
Gail J. Brown ◽  
Kitt Reinhardt
Keyword(s):  
Multilayer Structure ◽  
Negative Refraction ◽  
Low Cost ◽  
Negative Permittivity ◽  
Negative Permeability ◽  
Low Loss ◽  
Potential Applications ◽  
Composition Structure ◽  
Magnetic Resonances

An oxide-based multilayer structure was proposed to realize negative refraction. The multilayer composes of alternative layers having negative permittivity and negative permeability, respectively. In order to realize negative refraction, their dielectric and magnetic resonances of layers will be tuned to the frequency as close as possibly via changing their temperature, composition, structure, and so forth. Such oxide-based NIMs are attractive for their potential applications as optical super lenses, imagers, optical cloaking, sensors, and so forth, those are required with low-loss, low-cost, and good fabrication flexibility.

Square-shaped metal screens in the infrared to terahertz spectral region: Resonance frequency, band gap, and bandpass filter characteristics

2008 ◽  
Vol 104 (2) ◽  
pp. 023103 ◽  
Author(s):  
O. Sternberg ◽  
K. P. Stewart ◽  
Y. Hor ◽  
A. Bandyopadhyay ◽  
J. F. Federici ◽  
...  
Keyword(s):  
Resonance Frequency ◽  
Band Gap ◽  
Frequency Band ◽  
Spectral Region ◽  
Bandpass Filter

scholarly journals Analysis of Photosynthetic Systems and Their Applications with Mathematical and Computational Models

2020 ◽  
Vol 10 (19) ◽  
pp. 6821
Author(s):  
Shyam Badu ◽  
Roderick Melnik ◽  
Sundeep Singh
Keyword(s):  
Quantum Coherence ◽  
Density Functional ◽  
Computational Models ◽  
Environmental Science ◽  
Light Harvesting ◽  
Green Sulfur Bacteria ◽  
Theoretical Background ◽  
Light Harvesting Complexes ◽  
Chlorophyll Pigments ◽  
Potential Applications

In biological and life science applications, photosynthesis is an important process that involves the absorption and transformation of sunlight into chemical energy. During the photosynthesis process, the light photons are captured by the green chlorophyll pigments in their photosynthetic antennae and further funneled to the reaction center. One of the most important light harvesting complexes that are highly important in the study of photosynthesis is the membrane-attached Fenna–Matthews–Olson (FMO) complex found in the green sulfur bacteria. In this review, we discuss the mathematical formulations and computational modeling of some of the light harvesting complexes including FMO. The most recent research developments in the photosynthetic light harvesting complexes are thoroughly discussed. The theoretical background related to the spectral density, quantum coherence and density functional theory has been elaborated. Furthermore, details about the transfer and excitation of energy in different sites of the FMO complex along with other vital photosynthetic light harvesting complexes have also been provided. Finally, we conclude this review by providing the current and potential applications in environmental science, energy, health and medicine, where such mathematical and computational studies of the photosynthesis and the light harvesting complexes can be readily integrated.

scholarly journals Quantum coherence effects in a four-level diamond-shape atomic system

2009 ◽  
Vol 282 (14) ◽  
pp. 2870-2877 ◽  
Author(s):  
Bao-Quan Ou ◽  
Lin-Mei Liang ◽  
Cheng-Zu Li
Keyword(s):  
Quantum Coherence ◽  
Atomic System ◽  
Coherence Effects ◽  
Quantum Coherence Effects

scholarly journals A Novel Tunable Triple-Band Left-Handed Metamaterial

2017 ◽  
Vol 2017 ◽  
pp. 1-10
Author(s):  
Si Li ◽  
Atef Z. Elsherbeni ◽  
Wenhua Yu ◽  
Wenxing Li ◽  
Yunlong Mao
Keyword(s):  
Current Density ◽  
Surface Current ◽  
Wide Band ◽  
The Other ◽  
Negative Permittivity ◽  
Negative Permeability ◽  
Surface Current Density ◽  
Density Distributions ◽  
Left Handed ◽  
Triple Band

A novel tunable triple-band left-handed metamaterial (LHM) composed of a single-loop resonator (SLR) and a variable capacitor-loaded short wire pair (CL-SWP) printed on both sides of a substrate is presented in this paper. The CL-SWP-based metamaterial (MTM) is a novel single-sided LHM. It is theoretically analyzed capable of extracting tunable negative permeability and a wide-band negative permittivity. We ran simulations for the CL-SWP-based MTM, the SLR-based MTM, and the proposed LHM. Together with the measured results, it is identified that this novel LHM exhibits a tunable triple-band left-handed (LH) property. With the increase of the loaded capacitance, one LH band is relatively stable, while the other two are moving towards lower frequencies with their bandwidth getting wider and narrower, respectively. The surface current density distributions indicate that the first LH band is mainly decided by the SLR, one of the rest 2 LH bands is mainly decided by the CL-SWP, and the other one is decided by the SLR and CL-SWP together.

POSSIBLE EXISTENCE OF GRANULAR LEFT-HANDED MATERIALS BASED ON BRUGGEMAN FORMALISM

2010 ◽  
Vol 24 (27) ◽  
pp. 5469-5474
Author(s):  
WEIKAI XU ◽  
YANZHANG DONG ◽  
SHUTIAN LIU
Keyword(s):  
Negative Permittivity ◽  
Negative Permeability ◽  
Left Handed ◽  
Two Component ◽  
Current Stage

In the current stage, left-handed material (LHM) has aroused wide interest based on several basic prototypes such as metamaterials. In this work, we have theoretically investigated the possible existence of granular LHM by using the Bruggeman formalism. The Wiener bounds and the Hashin–Shtrikman bounds were invoked and some examples were represented. We had found that when the dissipations are increased adequately, the estimates of the Bruggeman formalism will lie within the two bounds rigorously, even if the two permittivities have real parts of opposite signs. Thus, one particulate LHM may be achieved by choosing the two component mediums with negative permittivity and negative permeability, respectively.

CONTROL OF ABSORPTION AND KERR NONLINEARITY BASED ON QUANTUM COHERENCE WITHOUT DRIVING FIELD

2010 ◽  
Vol 24 (30) ◽  
pp. 2921-2930 ◽  
Author(s):  
ZHONGHUA HUANG ◽  
AIXI CHEN ◽  
ZHAOCHU CHEN ◽  
LI DENG
Keyword(s):  
Quantum Coherence ◽  
Atomic System ◽  
Electromagnetically Induced Transparency ◽  
Kerr Nonlinearity ◽  
Linear Absorption ◽  
Driving Field ◽  
Spontaneously Generated Coherence ◽  
Traditional Scheme ◽  
Atomic Medium ◽  
Induced Transparency

In a three-level atomic system, the influences of spontaneously generated coherence on the linear absorption and the Kerr nonlinearity are investigated. Our studies show that properties of linear absorption can be dramatically affected by the effect of spontaneously generated coherence. With increase of intensities of spontaneously generated coherence, absorption inhibition will occur, and finally the atomic medium becomes transparent. Furthermore, we find that the Kerr nonlinearity can be obviously enhanced under the action of effects of spontaneously generated coherence. Comparing with traditional scheme of the electromagnetically induced transparency, absorption and Kerr nonlinearity can be controlled without need another driving field in our scheme.

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