Surface enhanced Raman scattering(SERS)is an efficient technique to detect low concentration molecules.In this work,periodical silicon nanowires(Si NWs)integrated with metal-insulator-metal(MIM)layers are employed as ...Surface enhanced Raman scattering(SERS)is an efficient technique to detect low concentration molecules.In this work,periodical silicon nanowires(Si NWs)integrated with metal-insulator-metal(MIM)layers are employed as SERS substrates.Laser interference lithography(LIL)combined with reactive ion etching(RIE)is used to fabricate large-area periodic nanostructures,followed by decorating the MIM layers.Compared to MIM disks array on Si surface,the SERS enhancement factor(EF)of the MIM structures on the Si NWs array can be increased up to 5 times,which is attributed to the enhanced electric field at the boundary of the MIM disks.Furthermore,high density of nanoparticles and nanogaps serving as hot spots on sidewall surfaces also contribute to the enhanced SERS signals.Via changing the thickness of the insulator layer,the plasmonic resonance can be tuned,which provides a new localized surface plasmon resonance(LSPR)characteristic for SERS applications.展开更多
A plasmonic waveguide coupled system that is composed of a square ring cavity and a metal-insulator-metal （MIM） waveguide with two silver baffles is proposed. The transmission and reflection properties of the propos...A plasmonic waveguide coupled system that is composed of a square ring cavity and a metal-insulator-metal （MIM） waveguide with two silver baffles is proposed. The transmission and reflection properties of the proposed plasmonic system are investigated numerically using the finite element method. The normalized Hz field distributions are calculated to analyze the transmission mode in the plasmonic system. The extreme destructive interference between light mode and dark mode causes plasmonically induced reflection （PIR） window in the transmission spectrum. The PIR window is fitted using the coupled mode theory. The analytical result agrees with the simulation result approximately. In addition, the PIR window can be controlled by adjusting structural parameters and filling different dielectric into the MIM waveguide and the square ring cavity. The results provide a new approach to designing plasmonic devices.展开更多
To increase the absorption in a thin layer of absorbing material （amorphous silicon, a-Si）, a light trapping design is presented. The designed structure incorporates periodic metal-insulator-metal waveguides to enha...To increase the absorption in a thin layer of absorbing material （amorphous silicon, a-Si）, a light trapping design is presented. The designed structure incorporates periodic metal-insulator-metal waveguides to enhance the optical path length of light within the solar cells. The new design can result in broadband optical absorption enhancement not only for transverse magnetic （TM）-polarized light, but also for transverse electric （TE）-polarized light. No plasmonic modes can be excited in TE-polarization, but because of the coupling into the a-Si planar waveguide guiding modes and the diffraction of light by the bottom periodic structures into higher diffraction orders, the total absorption in the active region is also increased. The results from rigorous coupled wave analysis show that the overall optical absorption in the active layer can be greatly enhanced by up to 40%. The designed structures presented in this paper can be integrated with back contact technology to potentially produce high-efficiency thin-film solar cell devices.展开更多
A plasmonic Mach-Zehnder interferometric sensor based on a semicircular aperture-slit nanostructure patterned on a metal-insulator-metal film is proposed and demonstrated by finite difference time domain（FDTD） simul...A plasmonic Mach-Zehnder interferometric sensor based on a semicircular aperture-slit nanostructure patterned on a metal-insulator-metal film is proposed and demonstrated by finite difference time domain（FDTD） simulation. Due to the interference between two different surface plasmon polariton modes in this design, the transmission spectra exhibit oscillation behaviors in a broad bandwidth, and can be readily tailored by changing the SPP path length and core layer thickness. Based on this principle, the characteristics of refractive index sensing are also demonstrated by simulation. This structure is illuminated with a collimated light source from the back side to avoid impacts on the interference. Meanwhile,these results show that the proposed structure is promising for portable, efficient, and sensitive biosensing applications.展开更多
Developing a convenient method that can be routinely applied for ascertaining proportions of different vegetable oils employed in commercial blended edible oils remains a significant challenge.We address this issue by...Developing a convenient method that can be routinely applied for ascertaining proportions of different vegetable oils employed in commercial blended edible oils remains a significant challenge.We address this issue by proposing a novel method for detecting volume fraction of different oils based on the fact that these oils are optically transparent and have slightly different indices of refraction at a given temperature and wavelength.Accordingly,we develop a highly sensitive sensor for measuring the index of refraction of oil blends based on Fano resonance spectra obtained using a metal-insulatormetal(MIM)waveguide structure comprising a gapped straight waveguide coupled with two L-shaped resonators.The index of refraction sensitivity and figure of merit of the structure are calculated based on modeling using the finite element method,and the waveguide structure is accordingly optimized by adjusting the different geometric parameters to achieve a high-quality Fano resonance spectrum.The optimized structure achieves an ultra-high refractive index sensitivity of 770 nm/RIU in terms of a refractive index unit(RIU)of 1.Moreover,a highly stable linear relationship is obtained between the refractive index of mixed edible oils and the resonance wavelength.Experimental results demonstrate that the proposed structure can detect slight changes in the volume fractions of the components in blended oils.展开更多
A metal-insulator-metal(MIM)-based arc-shaped resonator coupled with a rectangular stub(MARS) structure is proposed. This structure can generate two tunable Fano resonances originating from two different mechanisms. T...A metal-insulator-metal(MIM)-based arc-shaped resonator coupled with a rectangular stub(MARS) structure is proposed. This structure can generate two tunable Fano resonances originating from two different mechanisms. The structure has the advantage of being sensitive to the refractive index, and this feature makes it favorable for application in various microsensors. The relationship between the structural parameters and Fano resonance is researched using the finite element method(FEM) based on the software COMSOL Multiphysics 5.4. The simulation reveals that the sensitivity reaches1900 nm/refractive index unit(RIU), and the figure of merit(FOM) is 23.75.展开更多
Complex salt Co_2Cl_5(py)_5 (py=pyridine) was obtained by the reaction of CoCl_2·6H_2O with Bu_4NMnO_4 in pyridine in the presence of benzoic acid. It is monoclinic and crystallizes in space group P2_1/n, fw=690....Complex salt Co_2Cl_5(py)_5 (py=pyridine) was obtained by the reaction of CoCl_2·6H_2O with Bu_4NMnO_4 in pyridine in the presence of benzoic acid. It is monoclinic and crystallizes in space group P2_1/n, fw=690.64, a=28.652(5), b=14.108(4), c=7.424(3) ;β=90.09(1); V=3001(2)~3; Z=4, Dc=1.53g/cm^3. Final R factor is 0.041. The structure consists of a discrete cation [Co~ⅢCl_2(py)_4]^+ and an anion [Co~Ⅱ Cl_3(py)]^-. The Co~Ⅲ ion is coordinated by two Cl^- and four pyridine nitrogen atoms to form an octahedral geometry, and Co~Ⅱ is coordinated by three Cl^- and one pyridine nitrogen atom to form the apices of a tetrahedron. The variable-temperature magnetic susceptility measurement shows no magnet-exchange interaction between Co~Ⅲ and Co~Ⅱ ions.展开更多
The chiral feature of an optical field can be evaluated by the parameter of g-factor enhancement,which is helpful to enhance chiroptic signals from a chiral dipole.In this work,the superchiral spot has been theoretica...The chiral feature of an optical field can be evaluated by the parameter of g-factor enhancement,which is helpful to enhance chiroptic signals from a chiral dipole.In this work,the superchiral spot has been theoretically proposed in metal-insulator-metal waveguides.The g-factor enhancement of the superchiral spot can be enhanced by 67-fold more than that of circularly polarized light,and the spot is confined in the deep wavelength scale along each spatial dimension.Moreover,the position of the superchiral spot can be tuned by manipulating the incident field.The tunable superchiral spot may find applications in chiral imaging and sensing.展开更多
Broom-shaped structures are widely seen in transtensional basins, including those discovered in many sags of the Bohai Bay Basin. Broom-shaped transtensional structural zones are generally petroliferous and thus impor...Broom-shaped structures are widely seen in transtensional basins, including those discovered in many sags of the Bohai Bay Basin. Broom-shaped transtensional structural zones are generally petroliferous and thus important targets for hydrocarbon exploration. This study analyzed the evolution and genetic mechanisms of the broom-shaped transtensional structures in the Gaoqing area of the Dongying Sag using the 3D seismic flattening technique and a physical simulation experiment. Furthermore, the control effects of the broom-shaped transtensional structures on hydrocarbon accumulation and distribution were discussed. The research results are as follows. The Gaoqing area is of a broom-shaped transtensional structure in planar view, composed of several arc-shaped secondary faults intersecting with high-level main fault in the same direction. On the seismic section, it appears as a typical semi-flower-like structure. In the early stage (that is, during the deposition of the Kongdian Formation to the lower submember of the 4th member of the Shahejie Formation, Es4(L)), single-fault pattern consisting of single or multiple faults in alignment was developed under extensional stress. While with the change of structural stress (that is, during the deposition of the Es4(U) to the Es2(L)), more secondary faults were formed, and came in a pattern of broom-shaped structure together with the major fault. In the late stage (that is, during the deposition of the Es1 to the Guantao Formation), the en echelon fault pattern was formed, as the major fault broke into multiple secondary faults. The divergent end of the broom-shaped transtensional structure has many secondary faults developed, the fault planes are gentle, and small-scale fan deltas are the predominant type of deposits. The hydrocarbon tends to laterally migrate far away and accumulate mianly in structural and lithologic-structural traps. On the other hand, in the convergent end, the fault planes are relatively steep, resulting in small-scale subaqueous fans or large-scale deltas deposited along the major fault, with hydrocarbon accumulating minaly in structural-lithologic traps proximal to the provenances.展开更多
基金financial support from A*STAR,SERC 2014 Public Sector Research Funding (PSF) Grant (SERC Project No. 1421200080)
文摘Surface enhanced Raman scattering(SERS)is an efficient technique to detect low concentration molecules.In this work,periodical silicon nanowires(Si NWs)integrated with metal-insulator-metal(MIM)layers are employed as SERS substrates.Laser interference lithography(LIL)combined with reactive ion etching(RIE)is used to fabricate large-area periodic nanostructures,followed by decorating the MIM layers.Compared to MIM disks array on Si surface,the SERS enhancement factor(EF)of the MIM structures on the Si NWs array can be increased up to 5 times,which is attributed to the enhanced electric field at the boundary of the MIM disks.Furthermore,high density of nanoparticles and nanogaps serving as hot spots on sidewall surfaces also contribute to the enhanced SERS signals.Via changing the thickness of the insulator layer,the plasmonic resonance can be tuned,which provides a new localized surface plasmon resonance(LSPR)characteristic for SERS applications.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61605177,61275166,and 11504139)the National Science Fund for Distinguished Young Scholars,China(Grant No.61525107)+4 种基金the Natural Science Foundation of Jiangsu Province,China(Grant No.BK20140167)the Natural Science Foundation of Shanxi Province,China(Grant No.201601D011008)the Fund Program for the Scientific Activities of Selected Returned Overseas Professionals in Shanxi Province,Chinathe Program for the Top Young and Middle-aged Innovative Talents of Higher Learning Institutions of Shanxi Province,Chinathe North University of China Science Fund for Distinguished Young Scholars
文摘A plasmonic waveguide coupled system that is composed of a square ring cavity and a metal-insulator-metal （MIM） waveguide with two silver baffles is proposed. The transmission and reflection properties of the proposed plasmonic system are investigated numerically using the finite element method. The normalized Hz field distributions are calculated to analyze the transmission mode in the plasmonic system. The extreme destructive interference between light mode and dark mode causes plasmonically induced reflection （PIR） window in the transmission spectrum. The PIR window is fitted using the coupled mode theory. The analytical result agrees with the simulation result approximately. In addition, the PIR window can be controlled by adjusting structural parameters and filling different dielectric into the MIM waveguide and the square ring cavity. The results provide a new approach to designing plasmonic devices.
基金Project supported by the Postgraduate Innovation Foundation of Jiangsu Province,China (Grant No.CX09B 090Z)the Key Postgraduate Plan of Nanjing University of Science and Technology,China
文摘To increase the absorption in a thin layer of absorbing material （amorphous silicon, a-Si）, a light trapping design is presented. The designed structure incorporates periodic metal-insulator-metal waveguides to enhance the optical path length of light within the solar cells. The new design can result in broadband optical absorption enhancement not only for transverse magnetic （TM）-polarized light, but also for transverse electric （TE）-polarized light. No plasmonic modes can be excited in TE-polarization, but because of the coupling into the a-Si planar waveguide guiding modes and the diffraction of light by the bottom periodic structures into higher diffraction orders, the total absorption in the active region is also increased. The results from rigorous coupled wave analysis show that the overall optical absorption in the active layer can be greatly enhanced by up to 40%. The designed structures presented in this paper can be integrated with back contact technology to potentially produce high-efficiency thin-film solar cell devices.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51405240 and 61178044)the Natural Science Foundation of Jiangsu Province of China(Grant No.BK20161559)+1 种基金the Natural Science Foundation of the Higher Education Institutions of Jiangsu Province of China(Grant No.16KJB510018)University Postgraduate Research and Innovation Project of Jiangsu Province,China(Grant No.KYLX16 1289)
文摘A plasmonic Mach-Zehnder interferometric sensor based on a semicircular aperture-slit nanostructure patterned on a metal-insulator-metal film is proposed and demonstrated by finite difference time domain（FDTD） simulation. Due to the interference between two different surface plasmon polariton modes in this design, the transmission spectra exhibit oscillation behaviors in a broad bandwidth, and can be readily tailored by changing the SPP path length and core layer thickness. Based on this principle, the characteristics of refractive index sensing are also demonstrated by simulation. This structure is illuminated with a collimated light source from the back side to avoid impacts on the interference. Meanwhile,these results show that the proposed structure is promising for portable, efficient, and sensitive biosensing applications.
基金supported by the National Natural Science Foundation of China(Grant No.51965007)the“One thousand Young and Middle-Aged College and University Backbone Teachers Cultivation Program”of Guangxi,China(Grant No.2019)。
文摘Developing a convenient method that can be routinely applied for ascertaining proportions of different vegetable oils employed in commercial blended edible oils remains a significant challenge.We address this issue by proposing a novel method for detecting volume fraction of different oils based on the fact that these oils are optically transparent and have slightly different indices of refraction at a given temperature and wavelength.Accordingly,we develop a highly sensitive sensor for measuring the index of refraction of oil blends based on Fano resonance spectra obtained using a metal-insulatormetal(MIM)waveguide structure comprising a gapped straight waveguide coupled with two L-shaped resonators.The index of refraction sensitivity and figure of merit of the structure are calculated based on modeling using the finite element method,and the waveguide structure is accordingly optimized by adjusting the different geometric parameters to achieve a high-quality Fano resonance spectrum.The optimized structure achieves an ultra-high refractive index sensitivity of 770 nm/RIU in terms of a refractive index unit(RIU)of 1.Moreover,a highly stable linear relationship is obtained between the refractive index of mixed edible oils and the resonance wavelength.Experimental results demonstrate that the proposed structure can detect slight changes in the volume fractions of the components in blended oils.
基金supported in part by the National Natural Science Foundation of China (Grant Nos. 61875250 and 61975189)the Zhejiang Provincial Natural Science Foundation of China (Grant Nos. LD21F050001 and Y21F040001)+3 种基金the Key Research Project by Department of Water Resources of Zhejiang Province (Grant No. RA2101)the Key Research and Development Project of Zhejiang Province (Grant No. 2021C03019)the Key R&D Projects of Shanxi Province (Grant Nos. 201903D421032 and 01804D131038)the Scientific Research Foundation of Zhejiang University of Water Resources and Electric Power (Grant No. xky2022032)。
文摘A metal-insulator-metal(MIM)-based arc-shaped resonator coupled with a rectangular stub(MARS) structure is proposed. This structure can generate two tunable Fano resonances originating from two different mechanisms. The structure has the advantage of being sensitive to the refractive index, and this feature makes it favorable for application in various microsensors. The relationship between the structural parameters and Fano resonance is researched using the finite element method(FEM) based on the software COMSOL Multiphysics 5.4. The simulation reveals that the sensitivity reaches1900 nm/refractive index unit(RIU), and the figure of merit(FOM) is 23.75.
文摘Complex salt Co_2Cl_5(py)_5 (py=pyridine) was obtained by the reaction of CoCl_2·6H_2O with Bu_4NMnO_4 in pyridine in the presence of benzoic acid. It is monoclinic and crystallizes in space group P2_1/n, fw=690.64, a=28.652(5), b=14.108(4), c=7.424(3) ;β=90.09(1); V=3001(2)~3; Z=4, Dc=1.53g/cm^3. Final R factor is 0.041. The structure consists of a discrete cation [Co~ⅢCl_2(py)_4]^+ and an anion [Co~Ⅱ Cl_3(py)]^-. The Co~Ⅲ ion is coordinated by two Cl^- and four pyridine nitrogen atoms to form an octahedral geometry, and Co~Ⅱ is coordinated by three Cl^- and one pyridine nitrogen atom to form the apices of a tetrahedron. The variable-temperature magnetic susceptility measurement shows no magnet-exchange interaction between Co~Ⅲ and Co~Ⅱ ions.
基金supported by the National Natural Science Foundation of China(Nos.62075132 and 92050202)Natural Science Foundation of Shanghai(No.22ZR1443100).
文摘The chiral feature of an optical field can be evaluated by the parameter of g-factor enhancement,which is helpful to enhance chiroptic signals from a chiral dipole.In this work,the superchiral spot has been theoretically proposed in metal-insulator-metal waveguides.The g-factor enhancement of the superchiral spot can be enhanced by 67-fold more than that of circularly polarized light,and the spot is confined in the deep wavelength scale along each spatial dimension.Moreover,the position of the superchiral spot can be tuned by manipulating the incident field.The tunable superchiral spot may find applications in chiral imaging and sensing.
文摘Broom-shaped structures are widely seen in transtensional basins, including those discovered in many sags of the Bohai Bay Basin. Broom-shaped transtensional structural zones are generally petroliferous and thus important targets for hydrocarbon exploration. This study analyzed the evolution and genetic mechanisms of the broom-shaped transtensional structures in the Gaoqing area of the Dongying Sag using the 3D seismic flattening technique and a physical simulation experiment. Furthermore, the control effects of the broom-shaped transtensional structures on hydrocarbon accumulation and distribution were discussed. The research results are as follows. The Gaoqing area is of a broom-shaped transtensional structure in planar view, composed of several arc-shaped secondary faults intersecting with high-level main fault in the same direction. On the seismic section, it appears as a typical semi-flower-like structure. In the early stage (that is, during the deposition of the Kongdian Formation to the lower submember of the 4th member of the Shahejie Formation, Es4(L)), single-fault pattern consisting of single or multiple faults in alignment was developed under extensional stress. While with the change of structural stress (that is, during the deposition of the Es4(U) to the Es2(L)), more secondary faults were formed, and came in a pattern of broom-shaped structure together with the major fault. In the late stage (that is, during the deposition of the Es1 to the Guantao Formation), the en echelon fault pattern was formed, as the major fault broke into multiple secondary faults. The divergent end of the broom-shaped transtensional structure has many secondary faults developed, the fault planes are gentle, and small-scale fan deltas are the predominant type of deposits. The hydrocarbon tends to laterally migrate far away and accumulate mianly in structural and lithologic-structural traps. On the other hand, in the convergent end, the fault planes are relatively steep, resulting in small-scale subaqueous fans or large-scale deltas deposited along the major fault, with hydrocarbon accumulating minaly in structural-lithologic traps proximal to the provenances.
