The high frequency gravitational waves (around lOS-lO12 Hz) could interact with a specially designed electro- magnetic resonance system. It is found that the power of transverse perturbative photon flux (PPF) of a...The high frequency gravitational waves (around lOS-lO12 Hz) could interact with a specially designed electro- magnetic resonance system. It is found that the power of transverse perturbative photon flux (PPF) of an electromagnetic resonance system can be improved significantly by virtue of an astigmatic Caussian beam. Cor- respondingly the signal-to-noise ratio (SNR) would also be improved. When the eccentric ratio of waist satisfying w0x : w0y 〉 1, the peak value of signal photon flux could be raised by 2-4 times with typical systematic parameters, while the background photon flux would be depressed. Therefore, the ratio of transverse PPF to background photon flux (i.e., SNR) can be further improved 3-8 times with dimensionless amplitude of relic gravitational wave ht = 10-36.展开更多
This paper reports the design of a multiband metamaterial (MM) absorber in the terahertz region. Theoretical and simulated results show that the absorber has four distinct and strong absorption points at 1.69, 2.76,...This paper reports the design of a multiband metamaterial (MM) absorber in the terahertz region. Theoretical and simulated results show that the absorber has four distinct and strong absorption points at 1.69, 2.76, 3.41 and 5.06 THz, which are consistent with 'fingerprints' of some explosive materials. The retrieved material parameters show that the impedance of MM could be tuned to match approximately the impedance of the free space to minimise the reflectance at absorption frequencies and large power loss exists at absorption frequencies. The distribution of the power loss indicates that the absorber is an excellent electromagnetic wave collector: the wave is first trapped and reinforced in certain specific locations and then consumed. This multiband absorber has applications in the detection of explosives and materials characterisation.展开更多
A thin-flexible multiband terahertz metamaterial absorber (MA) has been investigated. Each unit cell of the MA consists of a simple metal structure, which includes the top metal resonator ring and the bottom metalli...A thin-flexible multiband terahertz metamaterial absorber (MA) has been investigated. Each unit cell of the MA consists of a simple metal structure, which includes the top metal resonator ring and the bottom metallic ground plane, separated by a thin-flexible dielectric spacer. Finite-difference time domain simulation indicates that this MA can achieve over 99% absorption at frequencies of 1.50 THz, 3.33 THz, and 5.40 THz by properly assembling the sandwiched structure. However, because of its asymmetric structure, the MA is polarization-sensitive and can tune the absorptivity of the second absorption peak by changing the incident polarization angle. The effect of the error of the structural parameters on the absorption efficiency is also carefully analyzed in detail to guide the fabrication. Moreover, the proposed MA exhibits high refractive-index sensing sensitivity, which has potential applications in multi-wavelength sensing in the terahertz region.展开更多
The broadband metamaterial perfect absorber has been extensively studied due to its excellent characteristics and promising application prospect.In this work a solar broadband metamaterial perfect absorber is proposed...The broadband metamaterial perfect absorber has been extensively studied due to its excellent characteristics and promising application prospect.In this work a solar broadband metamaterial perfect absorber is proposed based on the structure of the germanium(Ge)cone array and the indium arsenide(InAs)dielectric film on the gold(Au)substrate.The results show that the absorption covers the whole ultraviolet-visible and near-infrared range.For the case of A>99%,the absorption bandwidth reaches up to 1230 nm with a wavelength range varied from 200 nm to 1430 nm.The proposed absorber is able to absorb more than 98.7%of the solar energy in a solar spectrum from 200 nm to 3000 nm.The electromagnetic dipole resonance and the high-order modes of the Ge cone couple strongly to the incident optical field,which introduces a strong coupling with the solar radiation and produces an ultra-broadband absorption.The absorption spectrum can be feasibly manipulated via tuning the structural parameters,and the polarization insensitivity performance is particularly excellent.The proposed absorber can possess wide applications in active photoelectric effects,thermion modulators,and photoelectric detectors.展开更多
Abstract The generalized system function, H(s), directly associated with the radiated or scattered fields is presented to effectively analyze the special resonant behavior of electromagnetic open systems in this pap...Abstract The generalized system function, H(s), directly associated with the radiated or scattered fields is presented to effectively analyze the special resonant behavior of electromagnetic open systems in this paper, which is adaptively constructed by using the model-based parameter estimation (MBPE) technique in the complex frequency domain. By analyzing the characteristics of complex zeros, poles and residues of H(s) in a finite operational frequency band, we can effectively determine resonant frequencies and resonant intensity of electromagnetic open systems. It is known that an analysis of Q-factor of antenna and scattering systems has been an interesting and challenging problem. Based on H(s) and the complex frequency w theories, a complex frequency method for Q-factor of electromagnetic open systems is presented in this paper. Some examples of the practical antenna arrays are given to illustrate the applications and validity of the generalized system function theory proposed by this paper.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 11205254 and 61501069the Fundamental Research Funds for the Central Universities under Grant No 106112016CDJXY300002
文摘The high frequency gravitational waves (around lOS-lO12 Hz) could interact with a specially designed electro- magnetic resonance system. It is found that the power of transverse perturbative photon flux (PPF) of an electromagnetic resonance system can be improved significantly by virtue of an astigmatic Caussian beam. Cor- respondingly the signal-to-noise ratio (SNR) would also be improved. When the eccentric ratio of waist satisfying w0x : w0y 〉 1, the peak value of signal photon flux could be raised by 2-4 times with typical systematic parameters, while the background photon flux would be depressed. Therefore, the ratio of transverse PPF to background photon flux (i.e., SNR) can be further improved 3-8 times with dimensionless amplitude of relic gravitational wave ht = 10-36.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.60871027,60901029 and 61071058)the National Basic Research Program of China(Grant No.2009CB623306)Key Laboratory of Shaanxi Provincial Synthetic Electronic Information System Foundation,China(Grant No.200905A)
文摘This paper reports the design of a multiband metamaterial (MM) absorber in the terahertz region. Theoretical and simulated results show that the absorber has four distinct and strong absorption points at 1.69, 2.76, 3.41 and 5.06 THz, which are consistent with 'fingerprints' of some explosive materials. The retrieved material parameters show that the impedance of MM could be tuned to match approximately the impedance of the free space to minimise the reflectance at absorption frequencies and large power loss exists at absorption frequencies. The distribution of the power loss indicates that the absorber is an excellent electromagnetic wave collector: the wave is first trapped and reinforced in certain specific locations and then consumed. This multiband absorber has applications in the detection of explosives and materials characterisation.
基金Project supported by the National Natural Science Foundation of China(Grant No.11504006)the Key Scientific Research Project of Higher Education of Henan Province,China(Grant No.15A140002)the Science and Technology Planning Project of Henan Province,China(Grant No.142300410366)
文摘A thin-flexible multiband terahertz metamaterial absorber (MA) has been investigated. Each unit cell of the MA consists of a simple metal structure, which includes the top metal resonator ring and the bottom metallic ground plane, separated by a thin-flexible dielectric spacer. Finite-difference time domain simulation indicates that this MA can achieve over 99% absorption at frequencies of 1.50 THz, 3.33 THz, and 5.40 THz by properly assembling the sandwiched structure. However, because of its asymmetric structure, the MA is polarization-sensitive and can tune the absorptivity of the second absorption peak by changing the incident polarization angle. The effect of the error of the structural parameters on the absorption efficiency is also carefully analyzed in detail to guide the fabrication. Moreover, the proposed MA exhibits high refractive-index sensing sensitivity, which has potential applications in multi-wavelength sensing in the terahertz region.
基金Project supported by the Natural Science Foundation of Guangdong Province,China(Grant No.2018A030313854)the Science and Technology Program of Guangzhou City,China(Grant No.2019050001).
文摘The broadband metamaterial perfect absorber has been extensively studied due to its excellent characteristics and promising application prospect.In this work a solar broadband metamaterial perfect absorber is proposed based on the structure of the germanium(Ge)cone array and the indium arsenide(InAs)dielectric film on the gold(Au)substrate.The results show that the absorption covers the whole ultraviolet-visible and near-infrared range.For the case of A>99%,the absorption bandwidth reaches up to 1230 nm with a wavelength range varied from 200 nm to 1430 nm.The proposed absorber is able to absorb more than 98.7%of the solar energy in a solar spectrum from 200 nm to 3000 nm.The electromagnetic dipole resonance and the high-order modes of the Ge cone couple strongly to the incident optical field,which introduces a strong coupling with the solar radiation and produces an ultra-broadband absorption.The absorption spectrum can be feasibly manipulated via tuning the structural parameters,and the polarization insensitivity performance is particularly excellent.The proposed absorber can possess wide applications in active photoelectric effects,thermion modulators,and photoelectric detectors.
文摘Abstract The generalized system function, H(s), directly associated with the radiated or scattered fields is presented to effectively analyze the special resonant behavior of electromagnetic open systems in this paper, which is adaptively constructed by using the model-based parameter estimation (MBPE) technique in the complex frequency domain. By analyzing the characteristics of complex zeros, poles and residues of H(s) in a finite operational frequency band, we can effectively determine resonant frequencies and resonant intensity of electromagnetic open systems. It is known that an analysis of Q-factor of antenna and scattering systems has been an interesting and challenging problem. Based on H(s) and the complex frequency w theories, a complex frequency method for Q-factor of electromagnetic open systems is presented in this paper. Some examples of the practical antenna arrays are given to illustrate the applications and validity of the generalized system function theory proposed by this paper.