Bloch surface waves（BSWs） are excited in one-dimensional photonic crystals（Ph Cs） terminated by a graphene monolayer under the Kretschmann configuration. The field distribution and reflectance spectra are numerica...Bloch surface waves（BSWs） are excited in one-dimensional photonic crystals（Ph Cs） terminated by a graphene monolayer under the Kretschmann configuration. The field distribution and reflectance spectra are numerically calculated by the transverse magnetic method under transfer-matrix polarization, while the sensitivity is analyzed and compared with those of the surface plasmon resonance sensing method. It is found that the intensity of magnetic field is considerably enhanced in the region of the terminated layer of the multilayer stacks, and that BSW resonance appears only in the interface of the graphene and solution. Influences of the graphene layers and the thickness of a unit cell in Ph Cs on the reflectance are studied as well. In particular, by analyzing the performance of BSW sensors with the graphene monolayer,the wavelength sensitivity of the proposed sensor is 1040 nm/RIU whereas the angular sensitivity is 25.1°/RIU. In addition,the maximum of figure of merit can reach as high as 3000 RIU^-1. Thus, by integrating graphene in a simple Kretschmann structure, one can obtain an enhancement of the light–graphene interaction, which is prospective for creating label-free,low-cost and high-sensitivity optical biosensors.展开更多
A new type of device consisting of a lithium niobate film coupled with a distributed Bragg reflector(DBR)was theoretically proposed to explore and release Bloch surface waves for applications in sensing and detection....A new type of device consisting of a lithium niobate film coupled with a distributed Bragg reflector(DBR)was theoretically proposed to explore and release Bloch surface waves for applications in sensing and detection.The film and grating made of lithium niobate(LiNbO_(3))were placed on both sides of the DBR and a concentrated electromagnetic field was formed at the film layer.By adjusting the spatial incidence angle of the incident light,two detection and analysis modes were obtained,including surface diffraction detection and guided Bloch detection.Surface diffraction detection was used to detect the gas molecule concentrations,while guided Bloch detection was applied for the concentration detection of biomolecule-modulated biological solutions.According to the drift of the Fano curve,the average sensor sensitivities from the analysis of the two modes were 1560°/RIU and 1161°/RIU,and the maximum detection sensitivity reached2320/RIU and 2200°/RIU,respectively.This study revealed the potential application of LiNbO_(3)as a tunable material when combined with DBR to construct a new type of biosensor,which offered broad application prospects in Bloch surface wave biosensors.展开更多
This paper puts forward a novel method of measuring the thin period-structure-film thickness based on the Bloch surface wave(BSW) enhanced Goos–Hanchen(GH) shift in one-dimensional photonic crystal(1DPC). The BSW phe...This paper puts forward a novel method of measuring the thin period-structure-film thickness based on the Bloch surface wave(BSW) enhanced Goos–Hanchen(GH) shift in one-dimensional photonic crystal(1DPC). The BSW phenomenon appearing in 1DPC enhances the GH shift generated in the attenuated total internal reflection structure. The GH shift is closely related to the thickness of the film which is composed of layer-structure of 1DPC. The GH shifts under multiple different incident light conditions will be obtained by varying the wavelength and angle of the measured light, and the thickness distribution of the entire structure of 1DPC is calculated by the particle swarm optimization(PSO) algorithm.The relationship between the structure of a 1DPC film composed of TiO_(2) and SiO_(2) layers and the GH shift, is investigated.Under the specific photonic crystal structure and incident conditions, a giant GH shift, 5.1 × 10^(3) times the wavelength of incidence, can be obtained theoretically. Simulation and calculation results show that the thickness of termination layer and periodic structure bilayer of 1DPC film with 0.1-nm resolution can be obtained by measuring the GH shifts. The exact structure of a 1DPC film is innovatively measured by the BSW-enhanced GH shift.展开更多
In this paper, considering the Hirota and the Maxwell–Bloch （H-MB） equations which are governed by femtosecond pulse propagation through a two-level doped fiber system, we construct the Darboux transformation of th...In this paper, considering the Hirota and the Maxwell–Bloch （H-MB） equations which are governed by femtosecond pulse propagation through a two-level doped fiber system, we construct the Darboux transformation of this system through a linear eigenvalue problem. Using this Daurboux transformation, we generate multi-soliton, positon, and breather solutions （both bright and dark breathers） of the H-MB equations. Finally, we also construct the rogue wave solutions of the above system.展开更多
The elastic wave propagation phenomena in two-dimensional periodic beam lattices are studied by using the Bloch wave transform. The numerical modeling is applied to the hexagonal and the rectangular beam lattices, in ...The elastic wave propagation phenomena in two-dimensional periodic beam lattices are studied by using the Bloch wave transform. The numerical modeling is applied to the hexagonal and the rectangular beam lattices, in which, both the in-plane （with respect to the lattice plane） and out-of-plane waves are considered. The dispersion relations are obtained by calculating the Bloch eigenfrequencies and eigenmodes. The frequency bandgaps are observed and the influence of the elastic and geometric properties of the primitive cell on the bandgaps is studied. By analyzing the phase and the group velocities of the Bloch wave modes, the anisotropic behaviors and the dispersive characteristics of the hexagonal beam lattice with respect to the wave prop- agation are highlighted in high frequency domains. One im- portant result presented herein is the comparison between the first Bloch wave modes to the membrane and bend- ing/transverse shear wave modes of the classical equivalent homogenized orthotropic plate model of the hexagonal beam lattice. It is shown that, in low frequency ranges, the homog- enized plate model can correctly represent both the in-plane and out-of-plane dynamic behaviors of the beam lattice, its frequency validity domain can be precisely evaluated thanks to the Bloch modal analysis. As another important and original result, we have highlighted the existence of the retro- propagating Bloch wave modes with a negative group veloc- ity, and of the corresponding ＂retro-propagating＂ frequency bands.展开更多
Band gaps of elastic waves in 1-D phononic crystals with imperfect interfaces were studied. By using the transfer matrix method （TMM） and the Bloch wave theory in the periodic structure, the dispersion equation was ...Band gaps of elastic waves in 1-D phononic crystals with imperfect interfaces were studied. By using the transfer matrix method （TMM） and the Bloch wave theory in the periodic structure, the dispersion equation was derived for the periodically lami- nated binary system with imperfect interfaces （the traction vector jumps or the displacement vector jumps）. The dispersion equation was solved numerically and wave band gaps were obtained in the Brillouin zone. Band gaps in the case of imperfect interfaces were compared with that in the case of perfect interfaces. The influence of imperfect interfaces on wave band gaps and some interesting phenomena were discussed.展开更多
Periodic dielectric-loaded waveguide is one of the diaphragmatic waveguides. For the excellent mode-selective propagation ability, it is of value for applications in gyrotron-traveling-wave amplifiers （gyro-TWT）, ac...Periodic dielectric-loaded waveguide is one of the diaphragmatic waveguides. For the excellent mode-selective propagation ability, it is of value for applications in gyrotron-traveling-wave amplifiers （gyro-TWT）, accelerators, and other microwave propagation systems. This paper focuses on studying the application of the strong lossy-dielectric- loaded periodic waveguide in millimeter-wave gyro-TWT. It is revealed that due to the lossy property of the dielectric, the energy in the dielectric slots is absorbed effectively and the high order Bloch harmonics induced by the periodicity of the structure are suppressed, which changes the discrete spectrum under losstess condition into a continuous one. As a result, the periodicity of the system is severely suppressed and a mode in the hollow region could be approximated by a fast wave mode in an empty waveguide. These results bring specific guidance for the applications of the lossy dielectric-loaded waveguide in gyro-TWTs and other devices.展开更多
In this paper, a method based on the Dirichlet- to-Neumann map is developed for bandgap calculation of mixed in-plane waves propagating in 2D phononic crystals with square and triangular lattices. The method expresses...In this paper, a method based on the Dirichlet- to-Neumann map is developed for bandgap calculation of mixed in-plane waves propagating in 2D phononic crystals with square and triangular lattices. The method expresses the scattered fields in a unit cell as the cylindrical wave expansions and imposes the Bloch condition on the boundary of the unit cell. The Dirichlet-to-Neumann （DtN） map is applied to obtain a linear eigenvalue equation, from which the Bloch wave vectors along the irreducible Brillouin zone are calculated for a given frequency. Compared with other methods, the present method is memory-saving and time-saving. It can yield accurate results with fast convergence for various material combinations including those with large acoustic mismatch without extra computational cost. The method is also efficient for mixed fluid-solid systems because it considers the different wave modes in the fluid and solid as well as the proper fluid-solid interface condition.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61203211 and 41675154)the Six Major Talent Peak Expert of Jiangsu Province,China(Grant No.2015-XXRJ-014)the Natural Science Foundation of Jiangsu Province,China(Grant No.BK20141483)
文摘Bloch surface waves（BSWs） are excited in one-dimensional photonic crystals（Ph Cs） terminated by a graphene monolayer under the Kretschmann configuration. The field distribution and reflectance spectra are numerically calculated by the transverse magnetic method under transfer-matrix polarization, while the sensitivity is analyzed and compared with those of the surface plasmon resonance sensing method. It is found that the intensity of magnetic field is considerably enhanced in the region of the terminated layer of the multilayer stacks, and that BSW resonance appears only in the interface of the graphene and solution. Influences of the graphene layers and the thickness of a unit cell in Ph Cs on the reflectance are studied as well. In particular, by analyzing the performance of BSW sensors with the graphene monolayer,the wavelength sensitivity of the proposed sensor is 1040 nm/RIU whereas the angular sensitivity is 25.1°/RIU. In addition,the maximum of figure of merit can reach as high as 3000 RIU^-1. Thus, by integrating graphene in a simple Kretschmann structure, one can obtain an enhancement of the light–graphene interaction, which is prospective for creating label-free,low-cost and high-sensitivity optical biosensors.
基金Project supported by Natural Science Foundation of Jiangsu Province,China(Grant No.BK20180098)National Laboratory of Solid State Microstructures,Nanjing University(Grant No.M33042)。
文摘A new type of device consisting of a lithium niobate film coupled with a distributed Bragg reflector(DBR)was theoretically proposed to explore and release Bloch surface waves for applications in sensing and detection.The film and grating made of lithium niobate(LiNbO_(3))were placed on both sides of the DBR and a concentrated electromagnetic field was formed at the film layer.By adjusting the spatial incidence angle of the incident light,two detection and analysis modes were obtained,including surface diffraction detection and guided Bloch detection.Surface diffraction detection was used to detect the gas molecule concentrations,while guided Bloch detection was applied for the concentration detection of biomolecule-modulated biological solutions.According to the drift of the Fano curve,the average sensor sensitivities from the analysis of the two modes were 1560°/RIU and 1161°/RIU,and the maximum detection sensitivity reached2320/RIU and 2200°/RIU,respectively.This study revealed the potential application of LiNbO_(3)as a tunable material when combined with DBR to construct a new type of biosensor,which offered broad application prospects in Bloch surface wave biosensors.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.51575387 and 51827812)。
文摘This paper puts forward a novel method of measuring the thin period-structure-film thickness based on the Bloch surface wave(BSW) enhanced Goos–Hanchen(GH) shift in one-dimensional photonic crystal(1DPC). The BSW phenomenon appearing in 1DPC enhances the GH shift generated in the attenuated total internal reflection structure. The GH shift is closely related to the thickness of the film which is composed of layer-structure of 1DPC. The GH shifts under multiple different incident light conditions will be obtained by varying the wavelength and angle of the measured light, and the thickness distribution of the entire structure of 1DPC is calculated by the particle swarm optimization(PSO) algorithm.The relationship between the structure of a 1DPC film composed of TiO_(2) and SiO_(2) layers and the GH shift, is investigated.Under the specific photonic crystal structure and incident conditions, a giant GH shift, 5.1 × 10^(3) times the wavelength of incidence, can be obtained theoretically. Simulation and calculation results show that the thickness of termination layer and periodic structure bilayer of 1DPC film with 0.1-nm resolution can be obtained by measuring the GH shifts. The exact structure of a 1DPC film is innovatively measured by the BSW-enhanced GH shift.
基金Project supported by the Natural Science Foundation of Zhejiang Province of China (Grant No. LY12A01007)the National Natural Science Foundation of China (Grant Nos. 11201251, 10971109, and 11271210)+1 种基金K. C. Wong Magna Fund in Ningbo Universitythe DST,DAE-BRNS, UGC, and CSIR, Government of India, for the financial support through major projects
文摘In this paper, considering the Hirota and the Maxwell–Bloch （H-MB） equations which are governed by femtosecond pulse propagation through a two-level doped fiber system, we construct the Darboux transformation of this system through a linear eigenvalue problem. Using this Daurboux transformation, we generate multi-soliton, positon, and breather solutions （both bright and dark breathers） of the H-MB equations. Finally, we also construct the rogue wave solutions of the above system.
文摘The elastic wave propagation phenomena in two-dimensional periodic beam lattices are studied by using the Bloch wave transform. The numerical modeling is applied to the hexagonal and the rectangular beam lattices, in which, both the in-plane （with respect to the lattice plane） and out-of-plane waves are considered. The dispersion relations are obtained by calculating the Bloch eigenfrequencies and eigenmodes. The frequency bandgaps are observed and the influence of the elastic and geometric properties of the primitive cell on the bandgaps is studied. By analyzing the phase and the group velocities of the Bloch wave modes, the anisotropic behaviors and the dispersive characteristics of the hexagonal beam lattice with respect to the wave prop- agation are highlighted in high frequency domains. One im- portant result presented herein is the comparison between the first Bloch wave modes to the membrane and bend- ing/transverse shear wave modes of the classical equivalent homogenized orthotropic plate model of the hexagonal beam lattice. It is shown that, in low frequency ranges, the homog- enized plate model can correctly represent both the in-plane and out-of-plane dynamic behaviors of the beam lattice, its frequency validity domain can be precisely evaluated thanks to the Bloch modal analysis. As another important and original result, we have highlighted the existence of the retro- propagating Bloch wave modes with a negative group veloc- ity, and of the corresponding ＂retro-propagating＂ frequency bands.
基金supported by the National Natural Science Foundation of China (No.10672019)
文摘Band gaps of elastic waves in 1-D phononic crystals with imperfect interfaces were studied. By using the transfer matrix method （TMM） and the Bloch wave theory in the periodic structure, the dispersion equation was derived for the periodically lami- nated binary system with imperfect interfaces （the traction vector jumps or the displacement vector jumps）. The dispersion equation was solved numerically and wave band gaps were obtained in the Brillouin zone. Band gaps in the case of imperfect interfaces were compared with that in the case of perfect interfaces. The influence of imperfect interfaces on wave band gaps and some interesting phenomena were discussed.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 60871051,60871047 and 60971072)
文摘Periodic dielectric-loaded waveguide is one of the diaphragmatic waveguides. For the excellent mode-selective propagation ability, it is of value for applications in gyrotron-traveling-wave amplifiers （gyro-TWT）, accelerators, and other microwave propagation systems. This paper focuses on studying the application of the strong lossy-dielectric- loaded periodic waveguide in millimeter-wave gyro-TWT. It is revealed that due to the lossy property of the dielectric, the energy in the dielectric slots is absorbed effectively and the high order Bloch harmonics induced by the periodicity of the structure are suppressed, which changes the discrete spectrum under losstess condition into a continuous one. As a result, the periodicity of the system is severely suppressed and a mode in the hollow region could be approximated by a fast wave mode in an empty waveguide. These results bring specific guidance for the applications of the lossy dielectric-loaded waveguide in gyro-TWTs and other devices.
基金supported by the National Natural Science Foundation of China(51178037,10632020)the 973 State Key Development Program for Basic Research of China(2010CB732104)
文摘In this paper, a method based on the Dirichlet- to-Neumann map is developed for bandgap calculation of mixed in-plane waves propagating in 2D phononic crystals with square and triangular lattices. The method expresses the scattered fields in a unit cell as the cylindrical wave expansions and imposes the Bloch condition on the boundary of the unit cell. The Dirichlet-to-Neumann （DtN） map is applied to obtain a linear eigenvalue equation, from which the Bloch wave vectors along the irreducible Brillouin zone are calculated for a given frequency. Compared with other methods, the present method is memory-saving and time-saving. It can yield accurate results with fast convergence for various material combinations including those with large acoustic mismatch without extra computational cost. The method is also efficient for mixed fluid-solid systems because it considers the different wave modes in the fluid and solid as well as the proper fluid-solid interface condition.
