Taking inspiration from quantum parity–time(PT) symmetries that have gained immense popularity in the emerging fields of non-Hermitian optics and photonics, the interest of exploring more generalized gain-loss intera...Taking inspiration from quantum parity–time(PT) symmetries that have gained immense popularity in the emerging fields of non-Hermitian optics and photonics, the interest of exploring more generalized gain-loss interactions is never seen down. In this paper we theoretically present new fantastic properties through a zero-index metamaterial(ZIM) waveguide loaded gain and loss defects. For the case of epsilon-and-mu-near-zero(EMNZ) based ZIM medium, electromagnetic(EM)waves are cumulative and the system behaves as an amplifier when the loss cavity coefficient is greater than the gain cavity coefficient. Conversely, when loss is less than gain, EM waves are dissipated and the system behaves as an attenuator.Moreover, our investigation is extended to non-Hermitian scenarios characterized by tailored distributions of gain and loss in the epsilon-near-zero(ENZ) host medium. The transport effect in ZIM waveguide is amplified in one mode, while it is dissipative in the other mode, which breaks the common sense and its physic is analyzed by magnetic flux. That is which cavity has the smaller loss/gain coefficient, the larger its magnetic flux, which cavity dominates. This paper is of significant importance in the manipulation of electromagnetic waves and light amplification as well as the enhancement of matter interactions.展开更多
Metamaterials(MTM)can enhance the properties of microwaves and also exceed some limitations of devices used in technical practice.Note that the antenna is the element for realizing a microwave imaging(MWI)system since...Metamaterials(MTM)can enhance the properties of microwaves and also exceed some limitations of devices used in technical practice.Note that the antenna is the element for realizing a microwave imaging(MWI)system since it is where signal transmission and absorption occur.Ultra-Wideband(UWB)antenna superstrates with MTM elements to ensure the signal transmitted from the antenna reaches the tumor and is absorbed by the same antenna.The lack of conventional head imaging techniques,for instance,Magnetic Resonance Imaging(MRI)and Computerized Tomography(CT)-scan,has been demonstrated in the paper focusing on the point of failure of these techniques for prompt diagnosis and portable systems.Furthermore,the importance ofMWIhas been addressed elaborately to portray its effectiveness and aptness for a primary tumor diagnosis.Other than that,MTM element designs have been discussed thoroughly based on their performances towards the contributions to the better image resolution of MWI with detailed reasonings.This paper proposes the novel design of a Zeroindex Split RingResonator(SRR)MTMelement superstrate with a UWB antenna implemented in MWI systems for detecting tumor.The novel design of the MTM enables the realization of a high gain of a superstrate UWB antenna with the highest gain of 5.70 dB.Besides that,the MTM imitates the conduct of the zeroreflection phase on the resonance frequency,which does not exist.An antenna with an MTM unit is of a 7×4 and 10×5 Zero-index SRR MTM element that acts as a superstrate plane to the antenna.Apart from that,Rogers(RT5880)substrate material is employed to fabricate the designed MTM unit cell,with the following characteristics:0.51mm thickness,the loss tangent of 0.02,as well as the relative permittivity of 2.2,with Computer Simulation Technology(CST)performing the simulation and design.Both MTM unit cells of 7×4 and 10×5 attained 0°with respect to the reflection phase at the 2.70 GHz frequency band.The first design,MTM Antenna Design 1,consists of a 7×4 MTM unit cell that observed a rise of 5.70 dB with a return loss(S11)−20.007 dB at 2.70 GHz frequency.The second design,MTM Antenna Design 2,consists of 10×5 MTM unit cells that recorded a gain of 5.66 dB,having the return loss(S11)−19.734 dB at 2.70 GHz frequency.Comparing these two MTM elements superstrates with the antenna,one can notice that the 7×4 MTM element shape has a low number of the unit cell with high gain and is a better choice than the 10×5 MTM element in realizing MTM element superstrates antenna for MWI.展开更多
目的近零折射率(index near zero,INZ)模式在光通信和物理诊疗等领域展现出巨大应用潜力,但其调制通常依赖复杂的实验手段,这限制了其更广泛的应用。因此,设计并验证灵活可调的INZ模式及其应用场景在当下尤为重要。方法本研究提出两种...目的近零折射率(index near zero,INZ)模式在光通信和物理诊疗等领域展现出巨大应用潜力,但其调制通常依赖复杂的实验手段,这限制了其更广泛的应用。因此,设计并验证灵活可调的INZ模式及其应用场景在当下尤为重要。方法本研究提出两种基于钇铁石榴石(yttrium iron garnet,YIG)的亚波长磁光单向波导,通过理论分析波导结构中表面模式的色散曲线与波导参数的关系,明确调控INZ模式的理论并通过有限元法等技术验证理论结果。结果研究发现了新颖的宽带可调谐INZ模式。这些模式的频率明确依赖于外部磁场,具有可预测且精确可调的特性。基于此,本团队通过简单调控外部磁场,设计了宽带可调谐全光相位调控器及一种慢波INZ装置,并创新性地提出了一种基于可调控INZ模式的微波热疗理论。结论本团队设计的单向波导中的INZ模式具有可调控性和宽带的特性,利用单向INZ模式实现的功能器件为小型化全光通信和计算提供了新的可能性,也可用于如非介入式可控微波热疗等医疗领域。展开更多
基金Project supported by Scientific and Technological Innovation Program of Higher Education Institutions in Shanxi Province, China (Grant No. 2021L554)。
文摘Taking inspiration from quantum parity–time(PT) symmetries that have gained immense popularity in the emerging fields of non-Hermitian optics and photonics, the interest of exploring more generalized gain-loss interactions is never seen down. In this paper we theoretically present new fantastic properties through a zero-index metamaterial(ZIM) waveguide loaded gain and loss defects. For the case of epsilon-and-mu-near-zero(EMNZ) based ZIM medium, electromagnetic(EM)waves are cumulative and the system behaves as an amplifier when the loss cavity coefficient is greater than the gain cavity coefficient. Conversely, when loss is less than gain, EM waves are dissipated and the system behaves as an attenuator.Moreover, our investigation is extended to non-Hermitian scenarios characterized by tailored distributions of gain and loss in the epsilon-near-zero(ENZ) host medium. The transport effect in ZIM waveguide is amplified in one mode, while it is dissipative in the other mode, which breaks the common sense and its physic is analyzed by magnetic flux. That is which cavity has the smaller loss/gain coefficient, the larger its magnetic flux, which cavity dominates. This paper is of significant importance in the manipulation of electromagnetic waves and light amplification as well as the enhancement of matter interactions.
基金the Fundamental Research Grant Scheme (FRGS/1/2018/ICT06/UNIMAP/02/1)of the Ministry of Higher Education of Malaysia.
文摘Metamaterials(MTM)can enhance the properties of microwaves and also exceed some limitations of devices used in technical practice.Note that the antenna is the element for realizing a microwave imaging(MWI)system since it is where signal transmission and absorption occur.Ultra-Wideband(UWB)antenna superstrates with MTM elements to ensure the signal transmitted from the antenna reaches the tumor and is absorbed by the same antenna.The lack of conventional head imaging techniques,for instance,Magnetic Resonance Imaging(MRI)and Computerized Tomography(CT)-scan,has been demonstrated in the paper focusing on the point of failure of these techniques for prompt diagnosis and portable systems.Furthermore,the importance ofMWIhas been addressed elaborately to portray its effectiveness and aptness for a primary tumor diagnosis.Other than that,MTM element designs have been discussed thoroughly based on their performances towards the contributions to the better image resolution of MWI with detailed reasonings.This paper proposes the novel design of a Zeroindex Split RingResonator(SRR)MTMelement superstrate with a UWB antenna implemented in MWI systems for detecting tumor.The novel design of the MTM enables the realization of a high gain of a superstrate UWB antenna with the highest gain of 5.70 dB.Besides that,the MTM imitates the conduct of the zeroreflection phase on the resonance frequency,which does not exist.An antenna with an MTM unit is of a 7×4 and 10×5 Zero-index SRR MTM element that acts as a superstrate plane to the antenna.Apart from that,Rogers(RT5880)substrate material is employed to fabricate the designed MTM unit cell,with the following characteristics:0.51mm thickness,the loss tangent of 0.02,as well as the relative permittivity of 2.2,with Computer Simulation Technology(CST)performing the simulation and design.Both MTM unit cells of 7×4 and 10×5 attained 0°with respect to the reflection phase at the 2.70 GHz frequency band.The first design,MTM Antenna Design 1,consists of a 7×4 MTM unit cell that observed a rise of 5.70 dB with a return loss(S11)−20.007 dB at 2.70 GHz frequency.The second design,MTM Antenna Design 2,consists of 10×5 MTM unit cells that recorded a gain of 5.66 dB,having the return loss(S11)−19.734 dB at 2.70 GHz frequency.Comparing these two MTM elements superstrates with the antenna,one can notice that the 7×4 MTM element shape has a low number of the unit cell with high gain and is a better choice than the 10×5 MTM element in realizing MTM element superstrates antenna for MWI.
文摘目的近零折射率(index near zero,INZ)模式在光通信和物理诊疗等领域展现出巨大应用潜力,但其调制通常依赖复杂的实验手段,这限制了其更广泛的应用。因此,设计并验证灵活可调的INZ模式及其应用场景在当下尤为重要。方法本研究提出两种基于钇铁石榴石(yttrium iron garnet,YIG)的亚波长磁光单向波导,通过理论分析波导结构中表面模式的色散曲线与波导参数的关系,明确调控INZ模式的理论并通过有限元法等技术验证理论结果。结果研究发现了新颖的宽带可调谐INZ模式。这些模式的频率明确依赖于外部磁场,具有可预测且精确可调的特性。基于此,本团队通过简单调控外部磁场,设计了宽带可调谐全光相位调控器及一种慢波INZ装置,并创新性地提出了一种基于可调控INZ模式的微波热疗理论。结论本团队设计的单向波导中的INZ模式具有可调控性和宽带的特性,利用单向INZ模式实现的功能器件为小型化全光通信和计算提供了新的可能性,也可用于如非介入式可控微波热疗等医疗领域。
