The substitution of natural gas hydrates with CO2 offers a compelling dual advantage by enabling the extracting of CH4 while simultaneously sequestering CO2. This process, however, is intricately tied to the mechanical stability of CO2-CH4 heterohydrates. In this study, we report the mechanical properties and cage transformations in CO2-CH4 heterohydrates subjected to uniaxial straining via molecular dynamics (MD) simulations and machine learning (ML). Results indicate that guest molecule occupancy, the ratio of CO2 to CH4 and their spatial arrangements within heterohydrate structure greatly dictate the mechanical properties of CO2-CH4 heterohydrates including Young’s modulus, tensile strength, and critical strain. Notable, the introduction of CO2 within clathrate cages, particularly within 512 small cages, weakens the stability of CO2-CH4 heterohydrates in terms of mechanical properties. Upon critical strains, unconventional clathrate cages form, contributing to loading stress oscillation before fracture of heterohydrates. Intriguingly, predominant cage transformations, such as 51262 to 4151063 or 425864 and 512 to 425861 cages, are identified, in which 4151062 appears as primary intermediate cage that is able to transform into 4151063, 425862, 425863, 512 and 51262 cages, unveiling the dynamic nature of heterohydrate structures under straining.Additionally, machine learning (ML) models developed using MD data well predict the mechanical properties of heterohydrates, and underscore the critical influence of the spatial arrangement of guest molecules on the mechanical properties. These newly-developed ML models serve as valuable tools for accurately predicting the mechanical properties of heterohydrates. This study provides fresh insights into the mechanical properties and cage transformations in heterohydrates in response to strain, holding significant implications for environmentally sustainable utilization of CO2-CH4 heterohydrates.
{"title":"Mechanical properties and cage transformations in CO2-CH4 heterohydrates: a molecular dynamics and machine learning study","authors":"Yu Zhang, Xintong Liu, Qiao Shi, Yongxiao Qu, Yongchao Hao, Yuequn Fu, Jianyang Wu, Zhisen Zhang","doi":"10.1088/1361-6463/ad6dcf","DOIUrl":"https://doi.org/10.1088/1361-6463/ad6dcf","url":null,"abstract":"\u0000 The substitution of natural gas hydrates with CO2 offers a compelling dual advantage by enabling the extracting of CH4 while simultaneously sequestering CO2. This process, however, is intricately tied to the mechanical stability of CO2-CH4 heterohydrates. In this study, we report the mechanical properties and cage transformations in CO2-CH4 heterohydrates subjected to uniaxial straining via molecular dynamics (MD) simulations and machine learning (ML). Results indicate that guest molecule occupancy, the ratio of CO2 to CH4 and their spatial arrangements within heterohydrate structure greatly dictate the mechanical properties of CO2-CH4 heterohydrates including Young’s modulus, tensile strength, and critical strain. Notable, the introduction of CO2 within clathrate cages, particularly within 512 small cages, weakens the stability of CO2-CH4 heterohydrates in terms of mechanical properties. Upon critical strains, unconventional clathrate cages form, contributing to loading stress oscillation before fracture of heterohydrates. Intriguingly, predominant cage transformations, such as 51262 to 4151063 or 425864 and 512 to 425861 cages, are identified, in which 4151062 appears as primary intermediate cage that is able to transform into 4151063, 425862, 425863, 512 and 51262 cages, unveiling the dynamic nature of heterohydrate structures under straining.Additionally, machine learning (ML) models developed using MD data well predict the mechanical properties of heterohydrates, and underscore the critical influence of the spatial arrangement of guest molecules on the mechanical properties. These newly-developed ML models serve as valuable tools for accurately predicting the mechanical properties of heterohydrates. This study provides fresh insights into the mechanical properties and cage transformations in heterohydrates in response to strain, holding significant implications for environmentally sustainable utilization of CO2-CH4 heterohydrates.","PeriodicalId":507822,"journal":{"name":"Journal of Physics D: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141920226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-10DOI: 10.1088/1361-6463/ad6dd0
Jin-Young Choi, Junseok Ma, Hyunwoo Oh, Wook-Sung Kim
This paper introduces an electrically reconfigurable narrowband bandpass filter that exploits liquid-crystal technology. The filter uses two electrically-coupled open-loop resonators to produce two transmission zeros, resulting in a more compact structure than a single-open-loop resonator. The spacing between resonators contributes to easy manipulation of the fractional bandwidth (FBW) and return loss. Theoretical calculations of electrical length use multilayer microstrip line equations. Experimental results demonstrate that the center frequency can be tuned from 9.70 GHz to 10.86 GHz with a maximum bias voltage of 30 V, achieving a tuning range of 11.34%. With applied bias, the maximum FBW reaches 8.10% and the maximum return loss attains 15.97 dB in each biased state.
{"title":"Reconfigurable narrow-band bandpass filter using electrically-coupled open-loop resonators based on liquid crystals","authors":"Jin-Young Choi, Junseok Ma, Hyunwoo Oh, Wook-Sung Kim","doi":"10.1088/1361-6463/ad6dd0","DOIUrl":"https://doi.org/10.1088/1361-6463/ad6dd0","url":null,"abstract":"\u0000 This paper introduces an electrically reconfigurable narrowband bandpass filter that exploits liquid-crystal technology. The filter uses two electrically-coupled open-loop resonators to produce two transmission zeros, resulting in a more compact structure than a single-open-loop resonator. The spacing between resonators contributes to easy manipulation of the fractional bandwidth (FBW) and return loss. Theoretical calculations of electrical length use multilayer microstrip line equations. Experimental results demonstrate that the center frequency can be tuned from 9.70 GHz to 10.86 GHz with a maximum bias voltage of 30 V, achieving a tuning range of 11.34%. With applied bias, the maximum FBW reaches 8.10% and the maximum return loss attains 15.97 dB in each biased state.","PeriodicalId":507822,"journal":{"name":"Journal of Physics D: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141920227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-09DOI: 10.1088/1361-6463/ad6d79
M. K. Ajiriyanto, A. Anawati
The corrosion resistance of ceramic coatings developed by plasma electrolytic oxidation (PEO) can be improved by embedding particles. Optimizing the concentration of particles in the electrolyte is essential to obtain the best coating performance. This work aims to optimize the concentration of Y2O3 embeded in the PEO coatings on Zr-4 alloy to obtain the best corrosion resistance. Nanoparticles Y2O3 was suspended in the PEO electrolyte at a concentration of 2-4 g/l. PEO was conducted in a phosphate-silicate-based electrolyte at a constant DC current mode of 400 A/m2 for 10 min. The corrosion resistance was evaluated in a 4000 ppm H3BO3-2.5 ppm LiOH solution, and the high-temperature oxidation was studied in air at 600°C. The electrochemical and oxidation tests revealed a consistent result that the particle enrichment in the coatings enhanced corrosion resistance. The highest corrosion resistance was obtained for the coating formed in the 3 g/l Y2O3-containing electrolyte. The reason was related to the reduction of surface roughness and an increase in the tetragonal (t) ZrO2 phase. Moreover, the particle embedment on the coating surface ennobled the corrosion potential.
{"title":"Optimizing Additive Y2O3 Concentration For Improving Corrosion Resistance of Ceramic Coatings Formed by Plasma Electrolytic Oxidation on Zr-4 alloy","authors":"M. K. Ajiriyanto, A. Anawati","doi":"10.1088/1361-6463/ad6d79","DOIUrl":"https://doi.org/10.1088/1361-6463/ad6d79","url":null,"abstract":"\u0000 The corrosion resistance of ceramic coatings developed by plasma electrolytic oxidation (PEO) can be improved by embedding particles. Optimizing the concentration of particles in the electrolyte is essential to obtain the best coating performance. This work aims to optimize the concentration of Y2O3 embeded in the PEO coatings on Zr-4 alloy to obtain the best corrosion resistance. Nanoparticles Y2O3 was suspended in the PEO electrolyte at a concentration of 2-4 g/l. PEO was conducted in a phosphate-silicate-based electrolyte at a constant DC current mode of 400 A/m2 for 10 min. The corrosion resistance was evaluated in a 4000 ppm H3BO3-2.5 ppm LiOH solution, and the high-temperature oxidation was studied in air at 600°C. The electrochemical and oxidation tests revealed a consistent result that the particle enrichment in the coatings enhanced corrosion resistance. The highest corrosion resistance was obtained for the coating formed in the 3 g/l Y2O3-containing electrolyte. The reason was related to the reduction of surface roughness and an increase in the tetragonal (t) ZrO2 phase. Moreover, the particle embedment on the coating surface ennobled the corrosion potential.","PeriodicalId":507822,"journal":{"name":"Journal of Physics D: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141923718","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This work uses topology optimization methods to interactively design the plasma and metasurface loaded by resistance film, and obtains a composite absorber with good absorption effect. Genetic algorithm is used to find the minimum reflectivity of the composite absorber of plasma and metasurfaces, and after decoding, determine the corresponding topological structure of metasurface units and the optimal values of other parameters of the composite absorber. The optimized composite absorber maintains an absorption rate of over 95% in a wide frequency range of 5 GHz to 18 GHz. This broadband absorption effect is caused by the superposition of the absorption performance of plasma and metasurface. In addition, due to the central symmetric configuration of the metasurface unit, the composite absorber has good polarization insensitivity characteristics, and it still has broadband absorbing ability in the case of TE polarized waves and TM polarized waves obliquely incident. Thus, the proposed composite absorber designed based on topology optimization method has a wide frequency band, wide incidence angle, high absorption rate, and polarization insensitive absorbing effect. The topology optimization method is used for the design of the proposed composite absorber composed of plasma and metasurface, which does not overly rely on design experience of designer and provides an intelligent design method for stealth skin design in complex scattering media such as plasma.
{"title":"Plasma and metasurface composite absorber based on topology optimization","authors":"Shiping Guo, Guoxiang Dong, Jianzhong Chen, Xiaoming Chen","doi":"10.1088/1361-6463/ad6d7c","DOIUrl":"https://doi.org/10.1088/1361-6463/ad6d7c","url":null,"abstract":"\u0000 This work uses topology optimization methods to interactively design the plasma and metasurface loaded by resistance film, and obtains a composite absorber with good absorption effect. Genetic algorithm is used to find the minimum reflectivity of the composite absorber of plasma and metasurfaces, and after decoding, determine the corresponding topological structure of metasurface units and the optimal values of other parameters of the composite absorber. The optimized composite absorber maintains an absorption rate of over 95% in a wide frequency range of 5 GHz to 18 GHz. This broadband absorption effect is caused by the superposition of the absorption performance of plasma and metasurface. In addition, due to the central symmetric configuration of the metasurface unit, the composite absorber has good polarization insensitivity characteristics, and it still has broadband absorbing ability in the case of TE polarized waves and TM polarized waves obliquely incident. Thus, the proposed composite absorber designed based on topology optimization method has a wide frequency band, wide incidence angle, high absorption rate, and polarization insensitive absorbing effect. The topology optimization method is used for the design of the proposed composite absorber composed of plasma and metasurface, which does not overly rely on design experience of designer and provides an intelligent design method for stealth skin design in complex scattering media such as plasma.","PeriodicalId":507822,"journal":{"name":"Journal of Physics D: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141923358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-09DOI: 10.1088/1361-6463/ad6d7b
Xiaoyu Zhao, Xiaoke Gao, Jiawei Wang, Xikui Ma, T. Dong
Electromagnetic wave frequency conversion is a fundamental technique in telecommunications, especially the conversion from a single-frequency source to a multi-frequency output or a continuous spectra spread throughout space or time. By linking the differential intervals between the physical and virtual space with the ratio of the desired wavelength and the original wavelength, we can derive the mapping between the virtual and physical space-time within the space-time transformation optics (TO). With the functional magneto-electric coupling medium induced from the mapping, we demonstrate a class of converters that can generate arbitrary wavelength and location-dependent frequency distribution on a one-dimensional transmission line. Moreover, we have shown that multiple converters can be deliberately arranged both in the spatial and temporal dimension to achieve long-lasting time-varying frequency and space-time lens that can serve as a compressor and stretcher in chirp pulse amplification. Our concept for wave manipulation based on space-time TO may prepare the ground for a general solution to frequency conversion in various fields.
{"title":"Controllable location-dependent frequency conversion based on space-time transformation optics","authors":"Xiaoyu Zhao, Xiaoke Gao, Jiawei Wang, Xikui Ma, T. Dong","doi":"10.1088/1361-6463/ad6d7b","DOIUrl":"https://doi.org/10.1088/1361-6463/ad6d7b","url":null,"abstract":"\u0000 Electromagnetic wave frequency conversion is a fundamental technique in telecommunications, especially the conversion from a single-frequency source to a multi-frequency output or a continuous spectra spread throughout space or time. By linking the differential intervals between the physical and virtual space with the ratio of the desired wavelength and the original wavelength, we can derive the mapping between the virtual and physical space-time within the space-time transformation optics (TO). With the functional magneto-electric coupling medium induced from the mapping, we demonstrate a class of converters that can generate arbitrary wavelength and location-dependent frequency distribution on a one-dimensional transmission line. Moreover, we have shown that multiple converters can be deliberately arranged both in the spatial and temporal dimension to achieve long-lasting time-varying frequency and space-time lens that can serve as a compressor and stretcher in chirp pulse amplification. Our concept for wave manipulation based on space-time TO may prepare the ground for a general solution to frequency conversion in various fields.","PeriodicalId":507822,"journal":{"name":"Journal of Physics D: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141921376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-09DOI: 10.1088/1361-6463/ad6d77
Anatoly Vedyayev, Lingling L Tao, M. Zhuravlev
We consider two cases of spontaneous anomalous Hall current. In non-magnetic system with spin-orbit coupling, the applied bias results in the appearance of nonequilibrium magnetization and anomalous Hall current. The latter demonstrates non-linear dependence on the applied bias. In magnetic system with spin-orbit coupling, anomalous current appears without applied bias. We perform the calculation in the framework of free electron model, whereas common approach to this type of the phenomena is based on Berry connection. We demonstrate that the anomalous currents acquire a measurable magnitude for the reasonable parameters of the models.
{"title":"Spontaneous Anomalous Hall effects in magnetic and non-magnetic systems","authors":"Anatoly Vedyayev, Lingling L Tao, M. Zhuravlev","doi":"10.1088/1361-6463/ad6d77","DOIUrl":"https://doi.org/10.1088/1361-6463/ad6d77","url":null,"abstract":"\u0000 We consider two cases of spontaneous anomalous Hall current. In non-magnetic system with spin-orbit coupling, the applied bias results in the appearance of nonequilibrium magnetization and anomalous Hall current. The latter demonstrates non-linear dependence on the applied bias. In magnetic system with spin-orbit coupling, anomalous current appears without applied bias. We perform the calculation in the framework of free electron model, whereas common approach to this type of the phenomena is based on Berry connection. We demonstrate that the anomalous currents acquire a measurable magnitude for the reasonable parameters of the models.","PeriodicalId":507822,"journal":{"name":"Journal of Physics D: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141923316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-09DOI: 10.1088/1361-6463/ad6d7a
Jingxi Li, Jigeng Sun, Ziyang Ye, Zhihua Fan, Shaolin Zhou
In this paper, we propose an N-bit optical digital-to-analog converter (DAC) by integrating N pairs of 2 × 2 phase-change-based on-chip photonic switches and 2 × 2 multimode interference (MMI) splitters. The on-chip photonic switch is constructed by integrating the wavelength-selectable racetrack micro-ring resonator (MRR) and the phase change chalcogenide Ge2Sb2Se4Te (GSST). The GSST-integrated switch utilizes a racetrack resonator configuration for the accurate modulation of the resonant wavelength to prevent intercoupling between adjacent units. For electrothermal heating of the GSST film to trigger its phase transition for switchable control, an indium tin oxide (ITO) heater with a bowtie-shaped structure is integrated into the racetrack resonator. By numerical calculations, we demonstrate that an 8 V voltage pulse of 300 ns duration, with an energy consumption of 18.45 nJ, can transition the optical state from OFF state to ON state. Another 6 V voltage pulse of 250 ns duration, followed by a 4 V pulse of varying duration, with a total energy consumption of 34.78 nJ, can switch the optical state from ON state to OFF state. The asymmetric structure of the 2 × 2 MMI shows ultra-high transmittance approaching 50% in the through port (connected to the next order of MMI), enabling the creation of multistage cascaded MMI splitters with an output light power ratio close to 50%. Our results show that this configuration potentially offers a feasible solution for applications of optical digital-to-analog converters.
本文提出了一种 N 位光学数模转换器 (DAC)，它集成了 N 对 2 × 2 相变片上光子开关和 2 × 2 多模干涉 (MMI) 分路器。片上光子开关是通过集成波长可选的赛道微环谐振器（MRR）和相变钙钛矿 Ge2Sb2Se4Te（GSST）而构建的。集成了 GSST 的开关利用赛道谐振器配置来精确调制谐振波长，以防止相邻单元之间的互耦。为了对 GSST 薄膜进行电热加热，触发其相变以实现开关控制，我们在赛道谐振器中集成了一个弓形结构的氧化铟锡（ITO）加热器。通过数值计算，我们证明了持续时间为 300 ns 的 8 V 电压脉冲（能耗为 18.45 nJ）可以将光学状态从关态转换为开态。另一个持续时间为 250 ns 的 6 V 电压脉冲和一个持续时间不等的 4 V 脉冲（总能耗为 34.78 nJ）可以将光学状态从 ON 状态切换到 OFF 状态。2 × 2 MMI 的非对称结构在直通端口（与下一阶 MMI 相连）显示出接近 50% 的超高透过率，从而能够创建输出光功率比接近 50% 的多级级联 MMI 分光器。我们的研究结果表明，这种配置有可能为光学数模转换器的应用提供可行的解决方案。
{"title":"On-chip photonic digital-to-analog converter by phase-change-based bit control","authors":"Jingxi Li, Jigeng Sun, Ziyang Ye, Zhihua Fan, Shaolin Zhou","doi":"10.1088/1361-6463/ad6d7a","DOIUrl":"https://doi.org/10.1088/1361-6463/ad6d7a","url":null,"abstract":"\u0000 In this paper, we propose an N-bit optical digital-to-analog converter (DAC) by integrating N pairs of 2 × 2 phase-change-based on-chip photonic switches and 2 × 2 multimode interference (MMI) splitters. The on-chip photonic switch is constructed by integrating the wavelength-selectable racetrack micro-ring resonator (MRR) and the phase change chalcogenide Ge2Sb2Se4Te (GSST). The GSST-integrated switch utilizes a racetrack resonator configuration for the accurate modulation of the resonant wavelength to prevent intercoupling between adjacent units. For electrothermal heating of the GSST film to trigger its phase transition for switchable control, an indium tin oxide (ITO) heater with a bowtie-shaped structure is integrated into the racetrack resonator. By numerical calculations, we demonstrate that an 8 V voltage pulse of 300 ns duration, with an energy consumption of 18.45 nJ, can transition the optical state from OFF state to ON state. Another 6 V voltage pulse of 250 ns duration, followed by a 4 V pulse of varying duration, with a total energy consumption of 34.78 nJ, can switch the optical state from ON state to OFF state. The asymmetric structure of the 2 × 2 MMI shows ultra-high transmittance approaching 50% in the through port (connected to the next order of MMI), enabling the creation of multistage cascaded MMI splitters with an output light power ratio close to 50%. Our results show that this configuration potentially offers a feasible solution for applications of optical digital-to-analog converters.","PeriodicalId":507822,"journal":{"name":"Journal of Physics D: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141923313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-26DOI: 10.1088/1361-6463/ad67ea
F. Berkmann, P. Povolni, D. Schwarz, Inga Anita Fischer
Highly doped group IV semiconductors such as Ge or GeSn are promising candidates for plasmonic mid infrared applications. The lower effective mass of GeSn alloys in comparison to pure Ge can result in lower plasma wavelengths and extend the application wavelength range. Devices made from doped GeSn alloys, therefore, are one interesting route towards plasmonic applications in the MIR wavelength range, possibly extending to the NIR. Here, we specifically explore how spectrally narrow plasmonic resonances can be obtained in comb-like grating antennas by combining aspects of material growth with geometry optimization. We investigate both in simulation and in experiment how the interplay of localised surface plasmon resonances (LSPR) and Rayleigh anomalies (RA) can be tuned to achieve narrow extinction peaks originating from the resulting surface lattice resonances (SLR) generated in our antennas made from highly doped Ge1‑xSnx.Keywords: term, term, term
高掺杂 IV 族半导体（如 Ge 或 GeSn）是等离子体中红外应用的理想候选材料。与纯 Ge 相比，GeSn 合金的有效质量更低，因此等离子体波长更低，应用波长范围更广。因此，由掺杂 GeSn 合金制成的器件是在中红外波长范围内实现等离子应用的一条有趣途径，并有可能延伸到近红外。在此，我们特别探讨了如何通过将材料生长与几何优化相结合，在梳状光栅天线中获得光谱窄的等离子共振。我们在模拟和实验中研究了如何调整局部表面等离子体共振（LSPR）和瑞利反常（RA）的相互作用，以获得窄消光峰值，而窄消光峰值源于高掺杂 Ge1-xSnx 制成的天线中产生的表面晶格共振（SLR）。
{"title":"Influence of material and geometry parameters on resonance linewidths of plasmonic modes in gratings made from highly doped Ge1-xSnx","authors":"F. Berkmann, P. Povolni, D. Schwarz, Inga Anita Fischer","doi":"10.1088/1361-6463/ad67ea","DOIUrl":"https://doi.org/10.1088/1361-6463/ad67ea","url":null,"abstract":"\u0000 Highly doped group IV semiconductors such as Ge or GeSn are promising candidates for plasmonic mid infrared applications. The lower effective mass of GeSn alloys in comparison to pure Ge can result in lower plasma wavelengths and extend the application wavelength range. Devices made from doped GeSn alloys, therefore, are one interesting route towards plasmonic applications in the MIR wavelength range, possibly extending to the NIR. Here, we specifically explore how spectrally narrow plasmonic resonances can be obtained in comb-like grating antennas by combining aspects of material growth with geometry optimization. We investigate both in simulation and in experiment how the interplay of localised surface plasmon resonances (LSPR) and Rayleigh anomalies (RA) can be tuned to achieve narrow extinction peaks originating from the resulting surface lattice resonances (SLR) generated in our antennas made from highly doped Ge1‑xSnx.Keywords: term, term, term","PeriodicalId":507822,"journal":{"name":"Journal of Physics D: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141801373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-26DOI: 10.1088/1361-6463/ad67ec
Abdelrahman Farghali, Kazutoki Iwasa, Jongduk Kim, Junho Choi
Surface roughness control of the end products is increasingly becoming significant, especially with the miniaturization trends in the semiconductor industries. Ultra-thin amorphous carbon film offers a prime solution to optimize surface roughness due to its outstanding characteristics. In this study, hydrogenated amorphous carbon (a-C:H) films are deposited on two-dimensional quartz plates and three-dimensional quartz molds to evaluate the growth mechanisms and changes in the surface roughness, which is supported by molecular dynamics simulation. Results reveal that surface roughness encounters multiple variations until it reaches stable values. These fluctuations are categorized into four different stages which provide a concrete understanding of various growing mechanisms at each stage. Different behavior of the atoms in the top layers is recorded in the cases of normal and grazing incidents of carbon atoms. lower surface roughness values are obtained at low-angle deposition. Interestingly, surface smoothing is attained on the sidewalls of nanotrench mold where the deposition occurs with high incident ion angles.
{"title":"Atomic scale smoothing of nanoscale quartz mold using amorphous carbon films","authors":"Abdelrahman Farghali, Kazutoki Iwasa, Jongduk Kim, Junho Choi","doi":"10.1088/1361-6463/ad67ec","DOIUrl":"https://doi.org/10.1088/1361-6463/ad67ec","url":null,"abstract":"\u0000 Surface roughness control of the end products is increasingly becoming significant, especially with the miniaturization trends in the semiconductor industries. Ultra-thin amorphous carbon film offers a prime solution to optimize surface roughness due to its outstanding characteristics. In this study, hydrogenated amorphous carbon (a-C:H) films are deposited on two-dimensional quartz plates and three-dimensional quartz molds to evaluate the growth mechanisms and changes in the surface roughness, which is supported by molecular dynamics simulation. Results reveal that surface roughness encounters multiple variations until it reaches stable values. These fluctuations are categorized into four different stages which provide a concrete understanding of various growing mechanisms at each stage. Different behavior of the atoms in the top layers is recorded in the cases of normal and grazing incidents of carbon atoms. lower surface roughness values are obtained at low-angle deposition. Interestingly, surface smoothing is attained on the sidewalls of nanotrench mold where the deposition occurs with high incident ion angles.","PeriodicalId":507822,"journal":{"name":"Journal of Physics D: Applied Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141799133","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-26DOI: 10.1088/1361-6463/ad67eb
mingzhao chai
Multiply-accumulation are crucial computing operations in signal processing, numerical simulations, and machine learning. In recent years, optical analog approaches have demonstrated higher computing performance and better power efficiency than their digital counterparts. However, analog computing chips usually need large areas and complex structures for parallel computing, as a single device element only executes one computing operation at a single time. Here, we demonstrate frequency-domain computing using the nonlinear acoustic-wave devices on lithium niobate, featuring a normalized external second-harmonic generation conversion efficiency of ~ 5.7 × 10-4 W-1. The second-order sum-frequency nonlinear process of lithium niobate enables multiplication of inputs encoded in the frequency domain. Compared to the analog schemes, our device features a notably simpler design, and nanofabrication requires only one lift-off. Using a single acoustic-wave device within an area of 0.03 mm2, we can simultaneously conduct over 130,000 multiply-accumulation operations. Our acoustic-wave device shows applications in real and complex vector convolutions and image processing. This demonstration sets the stage for experimental realizations into frequency-domain integrated nonlinear acoustic computing systems, potentially shaping future developments in acoustic neural networks and quantum computing.
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