Julius Ratzenberger, Iuliia Kiseleva, Boris Koppitz, Elke Beyreuther, Manuel Zahn, Joshua Gössel, Peter A. Hegarty, Zeeshan H. Amber, Michael Rüsing, Lukas M. Eng
Ferroelectric domain walls (DWs) are promising structures for assembling future nano-electronic circuit elements on a larger scale since reporting domain wall currents of up to 1 mA per single DW. One key requirement hereto is their reproducible manufacturing by gaining preparative control over domain size and domain wall conductivity (DWC). To date, most works on DWC have focused on exploring the fundamental electrical properties of individual DWs within single-shot experiments, with an emphasis on quantifying the origins of DWC. Very few reports exist when it comes to comparing the DWC properties between two separate DWs, and literally nothing exists where issues of reproducibility in DWC devices have been addressed. To fill this gap while facing the challenge of finding guidelines for achieving predictable DWC performance, we report on a procedure that allows us to reproducibly prepare single hexagonal domains of a predefined diameter into uniaxial ferroelectric lithium niobate single crystals of 200 and 300 μm thickness, respectively. We show that the domain diameter can be controlled with an uncertainty of a few percent. As-grown DWs are then subjected to a standard procedure of current-limited high-voltage DWC enhancement, and they repetitively reach a DWC increase of six orders of magnitude. While all resulting DWs show significantly enhanced DWC values, their individual current–voltage (I–V) characteristics exhibit different shapes, which can be explained by variations in their 3D real structure reflecting local heterogeneities by defects, DW pinning, and surface-near DW inclination.
{"title":"Toward the reproducible fabrication of conductive ferroelectric domain walls into lithium niobate bulk single crystals","authors":"Julius Ratzenberger, Iuliia Kiseleva, Boris Koppitz, Elke Beyreuther, Manuel Zahn, Joshua Gössel, Peter A. Hegarty, Zeeshan H. Amber, Michael Rüsing, Lukas M. Eng","doi":"10.1063/5.0219300","DOIUrl":"https://doi.org/10.1063/5.0219300","url":null,"abstract":"Ferroelectric domain walls (DWs) are promising structures for assembling future nano-electronic circuit elements on a larger scale since reporting domain wall currents of up to 1 mA per single DW. One key requirement hereto is their reproducible manufacturing by gaining preparative control over domain size and domain wall conductivity (DWC). To date, most works on DWC have focused on exploring the fundamental electrical properties of individual DWs within single-shot experiments, with an emphasis on quantifying the origins of DWC. Very few reports exist when it comes to comparing the DWC properties between two separate DWs, and literally nothing exists where issues of reproducibility in DWC devices have been addressed. To fill this gap while facing the challenge of finding guidelines for achieving predictable DWC performance, we report on a procedure that allows us to reproducibly prepare single hexagonal domains of a predefined diameter into uniaxial ferroelectric lithium niobate single crystals of 200 and 300 μm thickness, respectively. We show that the domain diameter can be controlled with an uncertainty of a few percent. As-grown DWs are then subjected to a standard procedure of current-limited high-voltage DWC enhancement, and they repetitively reach a DWC increase of six orders of magnitude. While all resulting DWs show significantly enhanced DWC values, their individual current–voltage (I–V) characteristics exhibit different shapes, which can be explained by variations in their 3D real structure reflecting local heterogeneities by defects, DW pinning, and surface-near DW inclination.","PeriodicalId":15088,"journal":{"name":"Journal of Applied Physics","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142204279","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cong Chen, Peng Gao, Yaowei Dai, Hongzhong Cui, Xinyan Wang, Hai Liu
A highly sensitive terahertz stereo metasurface sensor, characterized by a high quality factor (Q-factor) and based on dual toroidal dipole (TD) resonance, has been proposed. The optimal structural parameters are ascertained by comparing the pertinent parameters of the stereo and planar structures in relation to TD modal excitation. The effective excitation of the TD mode is demonstrated using the calculations of multipole scattered power, reflection spectra, surface currents, electric fields, and magnetic field distributions. It is crucial that the stereo metasurface exhibits simplicity and that the dual TD resonance can be readily excited through simple adjustments in the distance and height of the intermediate gap. It also demonstrates exceptionally high sensitivity and Q-factor, both of which are essential for sensing applications. Moreover, the proposed stereo terahertz metasurface sensor still shows excellent sensing performance in a wide range of incidence angles (±40°), which is of great significance for practical applications. In conclusion, this structure offers a novel design framework for high-performance terahertz sensors based on the TD mode.
{"title":"The high-Q THz stereo metasurface sensor based on double toroidal dipole with wide operating angle bandwidth","authors":"Cong Chen, Peng Gao, Yaowei Dai, Hongzhong Cui, Xinyan Wang, Hai Liu","doi":"10.1063/5.0220850","DOIUrl":"https://doi.org/10.1063/5.0220850","url":null,"abstract":"A highly sensitive terahertz stereo metasurface sensor, characterized by a high quality factor (Q-factor) and based on dual toroidal dipole (TD) resonance, has been proposed. The optimal structural parameters are ascertained by comparing the pertinent parameters of the stereo and planar structures in relation to TD modal excitation. The effective excitation of the TD mode is demonstrated using the calculations of multipole scattered power, reflection spectra, surface currents, electric fields, and magnetic field distributions. It is crucial that the stereo metasurface exhibits simplicity and that the dual TD resonance can be readily excited through simple adjustments in the distance and height of the intermediate gap. It also demonstrates exceptionally high sensitivity and Q-factor, both of which are essential for sensing applications. Moreover, the proposed stereo terahertz metasurface sensor still shows excellent sensing performance in a wide range of incidence angles (±40°), which is of great significance for practical applications. In conclusion, this structure offers a novel design framework for high-performance terahertz sensors based on the TD mode.","PeriodicalId":15088,"journal":{"name":"Journal of Applied Physics","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142204272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The relative errors of virtual cathodes calculated by using the one-dimensional virtual cathode theory are analyzed and discussed. The studies of the error analysis show that the cathode temperature is the major factor affecting the calculated results of virtual cathodes, especially for calculations of the virtual cathode width. The smaller the virtual cathode produced by a hot cathode, the more significant the relative error of the virtual cathode caused by the uncertainties of electron emission parameters. Using the accurate cathode temperature, the potential barrier and the spatial width of virtual cathodes generated by a tungsten filament are calculated with experimental and theoretical electron emission parameters. The calculated results show that there is a strong linear correlation between the potential barrier of the virtual cathode and the heating current of the tungsten filament, which is independent of the electron collection current. With the increase in the heating current, the variation of the virtual cathode width is very sensitive to the relation between the electron collection current and the heating current.
{"title":"Calculation and error analysis of virtual cathode caused by a thermionic cathode","authors":"Jian-Quan Li, Shu-Han Li","doi":"10.1063/5.0217364","DOIUrl":"https://doi.org/10.1063/5.0217364","url":null,"abstract":"The relative errors of virtual cathodes calculated by using the one-dimensional virtual cathode theory are analyzed and discussed. The studies of the error analysis show that the cathode temperature is the major factor affecting the calculated results of virtual cathodes, especially for calculations of the virtual cathode width. The smaller the virtual cathode produced by a hot cathode, the more significant the relative error of the virtual cathode caused by the uncertainties of electron emission parameters. Using the accurate cathode temperature, the potential barrier and the spatial width of virtual cathodes generated by a tungsten filament are calculated with experimental and theoretical electron emission parameters. The calculated results show that there is a strong linear correlation between the potential barrier of the virtual cathode and the heating current of the tungsten filament, which is independent of the electron collection current. With the increase in the heating current, the variation of the virtual cathode width is very sensitive to the relation between the electron collection current and the heating current.","PeriodicalId":15088,"journal":{"name":"Journal of Applied Physics","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142204315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Dumas, F. Gustavo, M. Opprecht, G. Freychet, P. Gergaud, S. Kerdilès, S. Guillemin, J. L. Lábár, B. Pécz, F. Lefloch, F. Nemouchi
Laser annealing was employed to trigger the solid-state reaction of a thin Co film (2.5 nm) with undoped Si. A metastable disilicide layer was obtained after one laser pulse close to the melt threshold. Its diffraction pattern, relaxed lattice parameter, and residual resisitivity are consistent with the formation of the defective CsCl structure. The CoSi2 phase was found after prolonging the thermal treatment with additional pulses or rapid thermal annealing. Because CoSi is skipped in the phase sequence, CoSi2 layers are more uniform in thickness, have an increased superconductivity and a reduced formation temperature. This approach is compatible with the SALICIDE process and can be used to form smooth contacts in superconducting or regular transistors.
{"title":"Enhancing superconductivity in CoSi2 films with laser annealing","authors":"P. Dumas, F. Gustavo, M. Opprecht, G. Freychet, P. Gergaud, S. Kerdilès, S. Guillemin, J. L. Lábár, B. Pécz, F. Lefloch, F. Nemouchi","doi":"10.1063/5.0218950","DOIUrl":"https://doi.org/10.1063/5.0218950","url":null,"abstract":"Laser annealing was employed to trigger the solid-state reaction of a thin Co film (2.5 nm) with undoped Si. A metastable disilicide layer was obtained after one laser pulse close to the melt threshold. Its diffraction pattern, relaxed lattice parameter, and residual resisitivity are consistent with the formation of the defective CsCl structure. The CoSi2 phase was found after prolonging the thermal treatment with additional pulses or rapid thermal annealing. Because CoSi is skipped in the phase sequence, CoSi2 layers are more uniform in thickness, have an increased superconductivity and a reduced formation temperature. This approach is compatible with the SALICIDE process and can be used to form smooth contacts in superconducting or regular transistors.","PeriodicalId":15088,"journal":{"name":"Journal of Applied Physics","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142204271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Qian Guo, Yinchang Zhao, Yuming Sun, Jun Ni, Zhenhong Dai
This paper conducts a detailed study on the thermal transport and thermoelectric properties of Li2Rb(Cs)Bi and analyzes the optical phonon frequency shift caused by considering anharmonicity. We mainly focus on studying the microscopic mechanism of the difference in lattice thermal conductivity (κL) of the two materials. By calculating the group velocity, scattering rate, scattering phase space and scattering sub-process, it is concluded that κL is mainly dominated by the acoustic branch. Due to its small group velocity and large scattering rate, Li2CsBi has a low κL, which is 0.60 W m−1K−1 at 300 K. Research results show that n-type Li2CsBi has a higher ZT value of about 2.1 at T = 900 K, while p-type Li2RbBi has a higher ZT value of about 1.5 at the same temperature. These results provide an important theoretical basis for the application of Li2Rb(Cs)Bi in the field of thermoelectric conversion.
{"title":"Comparison of ultra-low lattice thermal conductivity of the full-Heusler compound Li2Rb(Cs)Bi after considering strong quartic anharmonicity","authors":"Qian Guo, Yinchang Zhao, Yuming Sun, Jun Ni, Zhenhong Dai","doi":"10.1063/5.0219749","DOIUrl":"https://doi.org/10.1063/5.0219749","url":null,"abstract":"This paper conducts a detailed study on the thermal transport and thermoelectric properties of Li2Rb(Cs)Bi and analyzes the optical phonon frequency shift caused by considering anharmonicity. We mainly focus on studying the microscopic mechanism of the difference in lattice thermal conductivity (κL) of the two materials. By calculating the group velocity, scattering rate, scattering phase space and scattering sub-process, it is concluded that κL is mainly dominated by the acoustic branch. Due to its small group velocity and large scattering rate, Li2CsBi has a low κL, which is 0.60 W m−1K−1 at 300 K. Research results show that n-type Li2CsBi has a higher ZT value of about 2.1 at T = 900 K, while p-type Li2RbBi has a higher ZT value of about 1.5 at the same temperature. These results provide an important theoretical basis for the application of Li2Rb(Cs)Bi in the field of thermoelectric conversion.","PeriodicalId":15088,"journal":{"name":"Journal of Applied Physics","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142204276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In terahertz (THz) wireless communication systems, non-diffraction vortex beams carrying an orbital angular momentum (OAM) have attracted extensive attention due to their ability to transmit information over long distances with high capacity. However, existing metasurfaces can only generate a single OAM mode non-diffracting vortex beam at reflection space for circular polarization (CP) incidence, limiting practical applications. To address this issue, we propose and design a polarization-frequency multiplexing transmissive THz metasurface to realize multi-mode non-diffracting vortex beams at linear polarization (LP) incidence. The meta-atom of this metasurface is composed of three anisotropic rectangular metallic structures embedded in vanadium dioxide (VO2) square rings, two circular aperture metallic grid layers, and four dielectric layers. By reasonably designing the size of the metal patch and the state of VO2, the designed metasurface can achieve polarization multiplexing and frequency multiplexing for LP incidence. Based on the phase response of the proposed meta-atoms, the transmissive metasurface can implement not only multi-mode non-diffraction vortex beams but also their space separation at two frequency ranges of 0.80–0.90 THz and 1.50–1.80 THz by changing the state of VO2. Therefore, the proposed multiple multiplexing metasurfaces can effectively shape the wavefront of non-diffraction vortex beams, which have broad application prospects in 6G THz communication.
{"title":"Multi-mode non-diffraction vortex beams enabled by polarization-frequency multiplexing transmissive terahertz metasurfaces","authors":"Mingzhong Wu, Xunjun He, Guangjun Lu, Zhaoxin Geng, Ying Zhang","doi":"10.1063/5.0222832","DOIUrl":"https://doi.org/10.1063/5.0222832","url":null,"abstract":"In terahertz (THz) wireless communication systems, non-diffraction vortex beams carrying an orbital angular momentum (OAM) have attracted extensive attention due to their ability to transmit information over long distances with high capacity. However, existing metasurfaces can only generate a single OAM mode non-diffracting vortex beam at reflection space for circular polarization (CP) incidence, limiting practical applications. To address this issue, we propose and design a polarization-frequency multiplexing transmissive THz metasurface to realize multi-mode non-diffracting vortex beams at linear polarization (LP) incidence. The meta-atom of this metasurface is composed of three anisotropic rectangular metallic structures embedded in vanadium dioxide (VO2) square rings, two circular aperture metallic grid layers, and four dielectric layers. By reasonably designing the size of the metal patch and the state of VO2, the designed metasurface can achieve polarization multiplexing and frequency multiplexing for LP incidence. Based on the phase response of the proposed meta-atoms, the transmissive metasurface can implement not only multi-mode non-diffraction vortex beams but also their space separation at two frequency ranges of 0.80–0.90 THz and 1.50–1.80 THz by changing the state of VO2. Therefore, the proposed multiple multiplexing metasurfaces can effectively shape the wavefront of non-diffraction vortex beams, which have broad application prospects in 6G THz communication.","PeriodicalId":15088,"journal":{"name":"Journal of Applied Physics","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142204278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cold spray is an effective method for surface coating, which has been applied in various engineering areas. However, it is difficult to directly observe the dynamic deformation process in experiments. This paper applies the molecular dynamics simulation to model the deposition of a monocrystalline Cu particle onto a Cu substrate and, subsequently, carries out a systematic study on the deposition mechanism and microstructure evolution. The results indicate that the deposition process consists of an impact stage and a relaxation stage. It is mainly the high speed collision and the friction following the collision that lead to particle deposition, which, under different circumstances, can be defined as surface deposition or penetration deposition. Two methods, namely, drastic shear deformation and cooling in the relaxation stage, can help form nanocrystallines. Jetting and melting are not the necessary factors for the deposition of nano-sized particles. The formation of dislocation lines is influenced by impact velocities. At lower impact velocities, the dislocation lines are mainly distributed near the contact surface. However, when the impact velocity is higher, dislocation lines are almost uniformly distributed in the particle.
{"title":"Atomistic simulation on the deposition behavior of cold spray","authors":"Jianrui Feng, Erfeng An, Wensen Zhao","doi":"10.1063/5.0218416","DOIUrl":"https://doi.org/10.1063/5.0218416","url":null,"abstract":"Cold spray is an effective method for surface coating, which has been applied in various engineering areas. However, it is difficult to directly observe the dynamic deformation process in experiments. This paper applies the molecular dynamics simulation to model the deposition of a monocrystalline Cu particle onto a Cu substrate and, subsequently, carries out a systematic study on the deposition mechanism and microstructure evolution. The results indicate that the deposition process consists of an impact stage and a relaxation stage. It is mainly the high speed collision and the friction following the collision that lead to particle deposition, which, under different circumstances, can be defined as surface deposition or penetration deposition. Two methods, namely, drastic shear deformation and cooling in the relaxation stage, can help form nanocrystallines. Jetting and melting are not the necessary factors for the deposition of nano-sized particles. The formation of dislocation lines is influenced by impact velocities. At lower impact velocities, the dislocation lines are mainly distributed near the contact surface. However, when the impact velocity is higher, dislocation lines are almost uniformly distributed in the particle.","PeriodicalId":15088,"journal":{"name":"Journal of Applied Physics","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142204273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The ionic conductivity at the grain boundaries (GBs) in oxide ceramics is typically several orders of magnitude lower than that within the grain interior. This detrimental GB effect is the main bottleneck for designing high-performance ceramic electrolytes intended for use in solid-state lithium-ion batteries, fuel cells, and electrolyzer cells. The macroscopic ionic conductivity in oxide ceramics is essentially governed by the underlying polycrystalline microstructures where GBs and grain morphology go hand in hand. This provides the possibility to enhance the ion conductivity by microstructure engineering. To this end, a thorough understanding of microstructure–property correlation is highly desirable. In this work, we investigate numerous polycrystalline microstructure samples with varying grain and grain boundary features. Their macroscopic ionic conductivities are numerically evaluated by the finite element homogenization method, whereby the GB resistance is explicitly regarded. The influence of different microstructural features on the effective ionic conductivity is systematically studied. The microstructure–property relationships are revealed. Additionally, a graph neural network-based machine learning model is constructed and trained. It can accurately predict the effective ionic conductivity for a given polycrystalline microstructure. This work provides crucial quantitative guidelines for optimizing the ionic conducting performance of oxide ceramics by tailoring microstructures.
{"title":"Unraveling impacts of polycrystalline microstructures on ionic conductivity of ceramic electrolytes by computational homogenization and machine learning","authors":"Xiang-Long Peng, Bai-Xiang Xu","doi":"10.1063/5.0223138","DOIUrl":"https://doi.org/10.1063/5.0223138","url":null,"abstract":"The ionic conductivity at the grain boundaries (GBs) in oxide ceramics is typically several orders of magnitude lower than that within the grain interior. This detrimental GB effect is the main bottleneck for designing high-performance ceramic electrolytes intended for use in solid-state lithium-ion batteries, fuel cells, and electrolyzer cells. The macroscopic ionic conductivity in oxide ceramics is essentially governed by the underlying polycrystalline microstructures where GBs and grain morphology go hand in hand. This provides the possibility to enhance the ion conductivity by microstructure engineering. To this end, a thorough understanding of microstructure–property correlation is highly desirable. In this work, we investigate numerous polycrystalline microstructure samples with varying grain and grain boundary features. Their macroscopic ionic conductivities are numerically evaluated by the finite element homogenization method, whereby the GB resistance is explicitly regarded. The influence of different microstructural features on the effective ionic conductivity is systematically studied. The microstructure–property relationships are revealed. Additionally, a graph neural network-based machine learning model is constructed and trained. It can accurately predict the effective ionic conductivity for a given polycrystalline microstructure. This work provides crucial quantitative guidelines for optimizing the ionic conducting performance of oxide ceramics by tailoring microstructures.","PeriodicalId":15088,"journal":{"name":"Journal of Applied Physics","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142226120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rui Jiang, Lei Gao, Lei Yang, Wenzhe He, Jun Wang, Qian Wu, Yong Sun, Quanying Wu, Yongqiang Chen
We present a novel approach for actively controlling electromagnetically induced transparency (EIT) analogs in a single-mode microstrip cavity. This cavity is side-coupled with a pair of varactor-loaded split-ring resonators (SRRs). The EIT-like effect is achieved through resonance hybridization between the paired SRRs with frequency detuning. The microstrip cavity is utilized to enhance the EIT-like transmission properties, including Q-factor and group delay. Varactor diodes, soldered at the gap of the SRRs, are biased electrically through a DC voltage source. This dynamic modulation setup allows for the tuning of the enhanced EIT analog. Experimental results demonstrate that the enhanced EIT-like transmission spectrum can be tuned reversibly by 378 MHz with respect to the transmission dip frequency of 2.464 GHz under the bias voltage ranging from 0 to 5 V. Simultaneously, the controlled transmission spectrum enables a remarkable change in group delay of 10.9 ns. Moreover, the modulation amplitude of the composite SRRs-cavity structure reaches a peak value of up to 34.5 dB, significantly higher than the 6.4 dB of the individual SRRs pair. These results hold promise for inspiring innovation in actively controlled photonic devices for practical applications.
我们提出了一种在单模微带腔中主动控制电磁诱导透明（EIT）类似物的新方法。该空腔侧面耦合了一对变容二极管加载的分环谐振器（SRR）。类似 EIT 的效果是通过频率失谐的成对 SRR 之间的共振杂化实现的。微带腔用于增强类 EIT 传输特性，包括 Q 因子和群延迟。焊接在 SRR 间隙的变容二极管通过直流电压源进行电偏压。这种动态调制设置允许对增强型 EIT 模拟进行调整。实验结果表明，在 0 至 5 V 的偏置电压下，增强型 EIT 类传输频谱可相对于 2.464 GHz 的传输骤降频率可逆地调整 378 MHz。与此同时，受控传输频谱还能使群延迟发生显著变化，达到 10.9 ns。此外，复合 SRRs-Cavity 结构的调制幅度峰值高达 34.5 dB，明显高于单个 SRRs 对的 6.4 dB。这些结果有望激发实际应用中主动控制光子器件的创新。
{"title":"Electromagnetic modulating action in a microstrip cavity with embedded two detuned resonators","authors":"Rui Jiang, Lei Gao, Lei Yang, Wenzhe He, Jun Wang, Qian Wu, Yong Sun, Quanying Wu, Yongqiang Chen","doi":"10.1063/5.0227168","DOIUrl":"https://doi.org/10.1063/5.0227168","url":null,"abstract":"We present a novel approach for actively controlling electromagnetically induced transparency (EIT) analogs in a single-mode microstrip cavity. This cavity is side-coupled with a pair of varactor-loaded split-ring resonators (SRRs). The EIT-like effect is achieved through resonance hybridization between the paired SRRs with frequency detuning. The microstrip cavity is utilized to enhance the EIT-like transmission properties, including Q-factor and group delay. Varactor diodes, soldered at the gap of the SRRs, are biased electrically through a DC voltage source. This dynamic modulation setup allows for the tuning of the enhanced EIT analog. Experimental results demonstrate that the enhanced EIT-like transmission spectrum can be tuned reversibly by 378 MHz with respect to the transmission dip frequency of 2.464 GHz under the bias voltage ranging from 0 to 5 V. Simultaneously, the controlled transmission spectrum enables a remarkable change in group delay of 10.9 ns. Moreover, the modulation amplitude of the composite SRRs-cavity structure reaches a peak value of up to 34.5 dB, significantly higher than the 6.4 dB of the individual SRRs pair. These results hold promise for inspiring innovation in actively controlled photonic devices for practical applications.","PeriodicalId":15088,"journal":{"name":"Journal of Applied Physics","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142204270","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Kan-Dapaah, J. A. Aidoo, B. Agyei-Tuffour, B. Mensah, A. Yaya, S. A. Abudu, S. W. K. Hatekah
Gold nanoparticles synthesized via honey-mediated chemical reduction have desirable features that make them ideal candidates for nanoparticle-assisted photothermal therapy (N-PTT). However, their photothermal properties have not been previously explored. In this study, after synthesis and characterization (structural and optical) of the HM-AuNPs, we investigated their photothermal conversion efficiency (η) and absorption cross section (σabs) in aqueous solution, cytotoxic effects in in vitro MDA-MB-468 breast cancer cell culture, and temperature profiles in agarose gel under 810 nm NIR irradiation. The results showed that ≈15 nm and primarily spherical HM-AuNPs had η values of up to 40% and an average σabs of 2.15±0.08×10−18 m2. Furthermore, cell viability was reduced to about 52% and the temperature profile in agarose gel had the typical radially increasing topology. Collectively, the findings show that HM-AuNPs can be used in N-PTT.
{"title":"Near-infrared irradiation study of honey-mediated Au nanoparticles for photothermal therapy","authors":"K. Kan-Dapaah, J. A. Aidoo, B. Agyei-Tuffour, B. Mensah, A. Yaya, S. A. Abudu, S. W. K. Hatekah","doi":"10.1063/5.0219146","DOIUrl":"https://doi.org/10.1063/5.0219146","url":null,"abstract":"Gold nanoparticles synthesized via honey-mediated chemical reduction have desirable features that make them ideal candidates for nanoparticle-assisted photothermal therapy (N-PTT). However, their photothermal properties have not been previously explored. In this study, after synthesis and characterization (structural and optical) of the HM-AuNPs, we investigated their photothermal conversion efficiency (η) and absorption cross section (σabs) in aqueous solution, cytotoxic effects in in vitro MDA-MB-468 breast cancer cell culture, and temperature profiles in agarose gel under 810 nm NIR irradiation. The results showed that ≈15 nm and primarily spherical HM-AuNPs had η values of up to 40% and an average σabs of 2.15±0.08×10−18 m2. Furthermore, cell viability was reduced to about 52% and the temperature profile in agarose gel had the typical radially increasing topology. Collectively, the findings show that HM-AuNPs can be used in N-PTT.","PeriodicalId":15088,"journal":{"name":"Journal of Applied Physics","volume":null,"pages":null},"PeriodicalIF":3.2,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142204275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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