A phoxonic crystal waveguide with the glide symmetry is designed,in which both electromagnetic and elastic waves can propagate along the glide plane at the same time.Due to the glide symmetry,the bands of the phoxonic...A phoxonic crystal waveguide with the glide symmetry is designed,in which both electromagnetic and elastic waves can propagate along the glide plane at the same time.Due to the glide symmetry,the bands of the phoxonic crystal super-cell degenerate in pairs at the boundary of the Brillouin zone.This is the so-called band-sticking effect and it causes the appearance of gapless guided-modes.By adjusting the magnitude of the glide dislocation the edge bandgaps,the bandgap of the guided-modes at the boundary of the Brillouin zone,can be further adjusted.The photonic and phononic guided-modes can then possess only one mode for a certain frequency with relatively low group velocities,achieving single-mode guided-bands with relatively flat dispersion relationship.In addition,there exists acousto-optic interaction in the cavity constructed by the glide plane.The proposed waveguide has potential applications in the design of novel optomechanical devices.展开更多
Cybernetic decision variants were analyzed in order to use for physical task of active noise cancelation. 10 dB mean active noise cancellation is demonstrated in two decades frequency band by usage of cybernetic decis...Cybernetic decision variants were analyzed in order to use for physical task of active noise cancelation. 10 dB mean active noise cancellation is demonstrated in two decades frequency band by usage of cybernetic decision for acoustical duct physical scale model. The used decision was found on minimization of acoustical field power transfer function from the beginning of waveguide to their end.展开更多
Photonic waveguides are the most fundamental element for photonic integrated circuits(PICs).Waveguide properties,such as propagation loss,modal areas,nonlinear coefficients,etc.,directly determine the functionalities ...Photonic waveguides are the most fundamental element for photonic integrated circuits(PICs).Waveguide properties,such as propagation loss,modal areas,nonlinear coefficients,etc.,directly determine the functionalities and performance of PICs.Recently,the emerging waveguides with bound states in the continuum(BICs)have opened new opportunities for PICs because of their special properties in resonance and radiation.Here,we review the recent progress of PICs composed of waveguides with BICs.First,fundamentals including background physics and design rules of a BIC-based waveguide will be introduced.Next,two types of BIC-based waveguide structures,including shallowly etched dielectric and hybrid waveguides,will be presented.Lastly,the challenges and opportunities of PICs with BICs will be discussed.展开更多
Two types of one-dimensional(1D)anti-PT-symmetric periodic ring optical waveguide networks,consisting of gain and loss materials,are constructed.The singular optical propagation properties of these networks are invest...Two types of one-dimensional(1D)anti-PT-symmetric periodic ring optical waveguide networks,consisting of gain and loss materials,are constructed.The singular optical propagation properties of these networks are investigated.The results show that the system composed of gain materials exhibits characteristics of ultra-strong transmission and bidirectional reflection.Conversely,the system composed of loss materials demonstrates equal transmittance and reflectance at some frequencies.In both the systems,a new type of total reflection phenomenon is observed.When the imaginary part of the refractive indices of waveguide segments is smaller than 10-5,the system shows bidirectional transparency with the transmittance tending to be 1 and reflectivity to be smaller than 10-8 at some bands.When the refractive indices of the waveguide segments are real,the system will be bidirectional transparent at the full band.These findings may deepen the understanding of anti-PT-symmetric optical systems and optical waveguide networks,and possess potential applications in efficient optical energy storage,ultra-sensitive optical filters,ultra-sensitive all-optical switches,integrated optical chips,stealth physics,and so on.展开更多
We theoretically investigate coherent scattering of single photons and quantum entanglement of two giant atoms with azimuthal angle differences in a waveguide system.Using the real-space Hamiltonian,analytical express...We theoretically investigate coherent scattering of single photons and quantum entanglement of two giant atoms with azimuthal angle differences in a waveguide system.Using the real-space Hamiltonian,analytical expressions are derived for the transport spectra scattered by these two giant atoms with four azimuthal angles.Fano-like resonance can be exhibited in the scattering spectra by adjusting the azimuthal angle difference.High concurrence of the entangled state for two atoms can be implemented in a wide angle-difference range,and the entanglement of the atomic states can be switched on/off by modulating the additional azimuthal angle differences from the giant atoms.This suggests a novel handle to effectively control the single-photon scattering and quantum entanglement.展开更多
Optical planar waveguides in Yba+-doped phosphate glasses are fabricated by implanting triple-energy helium ions. The guiding modes and the near-field intensity distribution are measured by using the prism-coupling m...Optical planar waveguides in Yba+-doped phosphate glasses are fabricated by implanting triple-energy helium ions. The guiding modes and the near-field intensity distribution are measured by using the prism-coupling method and the end-face coupling setup with a He Ne laser at 633 nm The intensity calculation method (ICM) is used to reconstruct the refractive index profile of the waveguide. The absorption and the fluorescence investigations reveal that the glass bulk features are well preserved in the active volumes of the waveguides, suggesting the fabricated structures for possible applications as waveguide lasers.展开更多
A novel nanolaser structure based on a hybrid plasmonic waveguide is proposed and investigated. The coupling between the metal nanowire and the high-index semiconductor nanowire with optical gain leads to a strong fie...A novel nanolaser structure based on a hybrid plasmonic waveguide is proposed and investigated. The coupling between the metal nanowire and the high-index semiconductor nanowire with optical gain leads to a strong field enhancement in the air gap region and low propagation loss, which enables the realization of lasing at the deep subwavelength scale.By optimizing the geometric parameters of the structure, a minimal lasing threshold is achieved while maintaining the capacity of ultra-deep subwavelength mode confinement. Compared with the previous coupled nanowire pair based hybrid plasmonic structure, a lower threshold can be obtained with the same geometric parameters. The proposed nanolaser can be integrated into a miniature chip as a nanoscale light source and has the potential to be widely used in optical communication and optical sensing technology.展开更多
The multimodal admittance method and its improvement are presented to deal with various aspects in underwater acoustics,mostly for the sound propagation in inhomogeneous waveguides with sound-speed profiles,arbitrary-...The multimodal admittance method and its improvement are presented to deal with various aspects in underwater acoustics,mostly for the sound propagation in inhomogeneous waveguides with sound-speed profiles,arbitrary-shaped liquid-like scatterers,and range-dependent environments.In all cases,the propagation problem governed by the Helmholtz equation is transformed into initial value problems of two coupled first-order evolution equations with respect to the modal components of field quantities(sound pressure and its derivative),by projecting the Helmholtz equation on a constructed orthogonal and complete local basis.The admittance matrix,which is the modal representation of Direchlet-to-Neumann operator,is introduced to compute the first-order evolution equations with no numerical instability caused by evanescent modes.The fourth-order Magnus scheme is used for the numerical integration of differential equations in the numerical implementation.The numerical experiments of sound field in underwater inhomogeneous waveguides generated by point sources are performed.Besides,the numerical results computed by simulation software COMSOL Multiphysics are given to validate the correction of the multimodal admittance method.It is shown that the multimodal admittance method is an efficient and stable numerical method to solve the wave propagation problem in inhomogeneous underwater waveguides with sound-speed profiles,liquid-like scatterers,and range-dependent environments.The extension of the method to more complicated waveguides such as horizontally stratified waveguides is available.展开更多
In this paper, we consider the inverse scattering problem of reconstructing a bounded obstacle in a three-dimensional planar waveguide from the scattered near-field data measured on a finite cylindrical surface contai...In this paper, we consider the inverse scattering problem of reconstructing a bounded obstacle in a three-dimensional planar waveguide from the scattered near-field data measured on a finite cylindrical surface containing the obstacle and corresponding to infinitely many incident point sources also placed on the measurement surface. The obstacle is allowed to be an impenetrable scatterer or a penetrable scatterer. We establish the validity of the factorization method with the nearfield data to characterize the obstacle in the planar waveguide by constructing an outgoing-to-incoming operator which is an integral operator defined on the measurement surface with the kernel given in terms of an infinite series.展开更多
A high efficiency grating coupler between single-mode fiber and silicon-on-insulator waveguide is designed by a formula method.Over 78.5%coupling efficiency(>-1.05 dB)with 3 dB bandwidth about 50 nm for one grating...A high efficiency grating coupler between single-mode fiber and silicon-on-insulator waveguide is designed by a formula method.Over 78.5%coupling efficiency(>-1.05 dB)with 3 dB bandwidth about 50 nm for one grating coupler is obtained experimentally and this result is the highest one as far as we know.This grating coupler is CMOS compatible which needs only one etch-step and is designed for a standard SOI chip without any Bragg reflector or bottom reflector.展开更多
We report on the fabrication of circular cladding waveguides with cross-section diameters of 60−120μm in Pr:YAG crystal by applying femtosecond laser inscription.The fabricated waveguides present 2D guidance on the c...We report on the fabrication of circular cladding waveguides with cross-section diameters of 60−120μm in Pr:YAG crystal by applying femtosecond laser inscription.The fabricated waveguides present 2D guidance on the cross-section and fairly low propagation losses.Multiple high-order guiding modes are observed in waveguides with different diameters.Corresponding simulation results reveal the origin of a specific kind of guiding modes.Confocal micro-Raman(μ-Raman)experiments demonstrate the modification effects in femtosecond laser affected areas and ascertain the refractive index induced guiding mechanism.In addition,luminescence emission properties of Pr3+ions at waveguide volume are well preserved during the femtosecond laser inscription process,which may result in a potential high-power visible waveguide laser.展开更多
The single photon scattering properties in a pair of waveguides coupled by a whispering-gallery resonator in- teracting with a semiconductor quantum dot are investigated theoretically. The two waveguides support four ...The single photon scattering properties in a pair of waveguides coupled by a whispering-gallery resonator in- teracting with a semiconductor quantum dot are investigated theoretically. The two waveguides support four possible ports for an incident single photon. The quantum dot is considered a V-type system. The incident direction-dependent single photon scattering properties are studied and equal-output probability from the four ports for a single photon incident is discussed. The influences of backscattering between the two modes of the whispering-gallery resonator for incident direction-dependent single photon scattering properties are also pre- sented.展开更多
With the help of the effective refractive index method we have numerically analyzed a multilayer planar waveguide structure and calculated the propagation constants, confinement factors, and transverse electric (TE) m...With the help of the effective refractive index method we have numerically analyzed a multilayer planar waveguide structure and calculated the propagation constants, confinement factors, and transverse electric (TE) modes. A five-layer waveguide model has been provided to analyze the electro-magne tic wave propagation process. The analysis method has been applied to the 980 nm laser with active layer of GaInAs/GaInAsP strained quantum wells, GaInAsP confinement layers and GaInP cap layers. By changing the thickness of confinement layers, we obtained confinement factor as high as 95% with higher TE modes TE1 and TE2. The results are in good agreement with the experiment by A. Al-Muhanna et al. and give the new idea to enhance output power of semiconductor lasers. The analysis method can also be extended to any other slab multilayer waveguide structures, and the results are useful to the fabrication of optic-electronic devices.展开更多
A simple solution for a multilayer metallic optical waveguide by transforming it intoan equivalent three-layer slab waveguide is presented. The dispersion relation of the equivalentthree-layer slab waveguide is solved...A simple solution for a multilayer metallic optical waveguide by transforming it intoan equivalent three-layer slab waveguide is presented. The dispersion relation of the equivalentthree-layer slab waveguide is solved by using a simple iterative formula. This method itself isexact and can approach any accuracy desired. Moreover, the numerical results for four-layer andfive-layer structures show that the second-order solution is also accurate enough. It is simple andhas the same form of expressions for TE and TM modes and for different layer structures.展开更多
Applying the spinor representation of the electromagnetic field, this paper present a quantum-mechanical description of waveguides. As an example of application, a potential qubit generated by photon tunnelling is dis...Applying the spinor representation of the electromagnetic field, this paper present a quantum-mechanical description of waveguides. As an example of application, a potential qubit generated by photon tunnelling is discussed.展开更多
We establish the superfluidity theory of coherent light in waveguides made of nonlinear polar crystals.It is found that the pairing state of photons in a nonlinear polar crystal is the photonic superfluid state.The ph...We establish the superfluidity theory of coherent light in waveguides made of nonlinear polar crystals.It is found that the pairing state of photons in a nonlinear polar crystal is the photonic superfluid state.The photon-photon interaction potential is an attractive effective interaction by exchange of virtual optical phonons.In the traveling-wave pairing state of photons,the photon number is conserved,which is similar to the Bose-Einstein condensation(BEC) state of photons.In analogy to the BCS-BEC crossover theory of superconductivity,we derive a set of coupled order parameter and number equations,which determine the solution of the traveling-wave superfluid state of photons.This solution gives the critical velocity of light in a self-focusing nonlinear waveguide.The most important property of the photonic superfluid state is that the system of photon pairs evolves without scattering attenuations.展开更多
On the basis of two-dimensional amorphous photonic materials, we have designed a novel waveguide by inserting thinner cylindrical inclusions in the centre of basic hexagonal units of the amorphous structure along a gi...On the basis of two-dimensional amorphous photonic materials, we have designed a novel waveguide by inserting thinner cylindrical inclusions in the centre of basic hexagonal units of the amorphous structure along a given path. This waveguide in amorphous structure is similar to the coupled resonator optical waveguides in periodic photonic crystals. The transmission of this waveguide for S-polarized waves is investigated by a multiple-scattering method. Compared with the conventional waveguide by removing a line of cells from amorphous photonic materials, the guiding properties of this waveguide, including the transmissivity and bandwidth, are improved significantly. Then we study the effect of various types of positional disorder on the functionality of this device. Our results show that the waveguide performance is quite sensitive to the disorder located on the boundary layer of the waveguide, but robust against the disorder in the other area in amorphous structure except the waveguide border. This disorder effect in amorphous photonic materials is similar to the case in periodic photonic crystals.展开更多
We report on the fabrication of the lO-mm-long lithium niobate ridge waveguide and its supercontinuum gen- eration at near-visible wavelengths (around 800hm). The waveguides are fabricated by a combination of MeV co...We report on the fabrication of the lO-mm-long lithium niobate ridge waveguide and its supercontinuum gen- eration at near-visible wavelengths (around 800hm). The waveguides are fabricated by a combination of MeV copper ion implantation followed by wet etching in a proton exchanged lithium niobate planar waveguide. Using a mode-locked Ti:sapphire laser with a central wavelength of 800nm, the generated broadest supereontinuum through the ridge waveguides spans 302 nm (at -30 dB points), from 693 to 995 nm. Temporal coherence proper- ties of the supercontinuum are experimentally studied by a Michelson interferometer and the coherence length of the broadest supercontinuum is measured to be 5.2 μm. Our results offer potential for a compact and integrated supercontinuum source for applications including bio-imaging, spectroscopy and optical communication.展开更多
The graphene-based double-barrier waveguides induced by electric field have been investigated. The guided modes can only exist in the case of Klein tunneling, and the fundamental mode is absent. The guided modes in th...The graphene-based double-barrier waveguides induced by electric field have been investigated. The guided modes can only exist in the case of Klein tunneling, and the fundamental mode is absent. The guided modes in the single-barrier waveguide split into symmetric and antisymmetric modes with different incident angles in the double-barrier waveguide. The phase difference between electron states and hole states is also discussed. The phase difference for the two splitting modes is close to each other and increases with the order of guided modes. These phenomena can be helpful for the potential applications in graphene-based optoelectronic devices.展开更多
A Nd:CLNGG waveguide structure operated at wavelengths of both 632.8 nm and 1539 nm was demonstrated for the first time to our knowledge, which was produced by the 480-keV H+ ion implantation with a dose of 1.0×...A Nd:CLNGG waveguide structure operated at wavelengths of both 632.8 nm and 1539 nm was demonstrated for the first time to our knowledge, which was produced by the 480-keV H+ ion implantation with a dose of 1.0× 10^17 protons/cm2, Its propagating modes at 632.8 nm and 1539 nm were measured by the well-known prism coupling technique. The refractive index profile at either 632.8-nm wavelength or 1539-nm wavelength was optical barrier type in the proton-implanted Nd:CLNGG crystal optical waveguide, which was calculated by using the reflectivity calculation method. The near-field light intensity distributions were also simulated by the finite-difference beam propagation method in the visible and nearinfrared bands.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.12064025)the Natural Science Foundation of Jiangxi Province,China(Grant No.20212ACB202006)+1 种基金the Major Discipline Academic and Technical Leaders Training Program of Jiangxi Province,China(Grant No.20204BCJ22012)the Open Project of the Key Laboratory of Radar Imaging and Microwave Photonic Technology of the Education Ministry of China.
文摘A phoxonic crystal waveguide with the glide symmetry is designed,in which both electromagnetic and elastic waves can propagate along the glide plane at the same time.Due to the glide symmetry,the bands of the phoxonic crystal super-cell degenerate in pairs at the boundary of the Brillouin zone.This is the so-called band-sticking effect and it causes the appearance of gapless guided-modes.By adjusting the magnitude of the glide dislocation the edge bandgaps,the bandgap of the guided-modes at the boundary of the Brillouin zone,can be further adjusted.The photonic and phononic guided-modes can then possess only one mode for a certain frequency with relatively low group velocities,achieving single-mode guided-bands with relatively flat dispersion relationship.In addition,there exists acousto-optic interaction in the cavity constructed by the glide plane.The proposed waveguide has potential applications in the design of novel optomechanical devices.
文摘Cybernetic decision variants were analyzed in order to use for physical task of active noise cancelation. 10 dB mean active noise cancellation is demonstrated in two decades frequency band by usage of cybernetic decision for acoustical duct physical scale model. The used decision was found on minimization of acoustical field power transfer function from the beginning of waveguide to their end.
基金Project supported by the National Key Research and Development Program of China (2021YFB2800404)National Natural Science Foundation of China (62105283)+1 种基金Zhejiang Provincial Natural Science Foundation of China (LDT23F04012F05)Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang (2021R01001)
文摘Photonic waveguides are the most fundamental element for photonic integrated circuits(PICs).Waveguide properties,such as propagation loss,modal areas,nonlinear coefficients,etc.,directly determine the functionalities and performance of PICs.Recently,the emerging waveguides with bound states in the continuum(BICs)have opened new opportunities for PICs because of their special properties in resonance and radiation.Here,we review the recent progress of PICs composed of waveguides with BICs.First,fundamentals including background physics and design rules of a BIC-based waveguide will be introduced.Next,two types of BIC-based waveguide structures,including shallowly etched dielectric and hybrid waveguides,will be presented.Lastly,the challenges and opportunities of PICs with BICs will be discussed.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11674107,61475049,11775083,61774062,and 61771205).
文摘Two types of one-dimensional(1D)anti-PT-symmetric periodic ring optical waveguide networks,consisting of gain and loss materials,are constructed.The singular optical propagation properties of these networks are investigated.The results show that the system composed of gain materials exhibits characteristics of ultra-strong transmission and bidirectional reflection.Conversely,the system composed of loss materials demonstrates equal transmittance and reflectance at some frequencies.In both the systems,a new type of total reflection phenomenon is observed.When the imaginary part of the refractive indices of waveguide segments is smaller than 10-5,the system shows bidirectional transparency with the transmittance tending to be 1 and reflectivity to be smaller than 10-8 at some bands.When the refractive indices of the waveguide segments are real,the system will be bidirectional transparent at the full band.These findings may deepen the understanding of anti-PT-symmetric optical systems and optical waveguide networks,and possess potential applications in efficient optical energy storage,ultra-sensitive optical filters,ultra-sensitive all-optical switches,integrated optical chips,stealth physics,and so on.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12365003,12364024,and 11864014)the Jiangxi Provincial Natural Science Foundation(Grant Nos.20212BAB201014 and 20224BAB201023)。
文摘We theoretically investigate coherent scattering of single photons and quantum entanglement of two giant atoms with azimuthal angle differences in a waveguide system.Using the real-space Hamiltonian,analytical expressions are derived for the transport spectra scattered by these two giant atoms with four azimuthal angles.Fano-like resonance can be exhibited in the scattering spectra by adjusting the azimuthal angle difference.High concurrence of the entangled state for two atoms can be implemented in a wide angle-difference range,and the entanglement of the atomic states can be switched on/off by modulating the additional azimuthal angle differences from the giant atoms.This suggests a novel handle to effectively control the single-photon scattering and quantum entanglement.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 61077070, 10876009, and 51002181)the One Hundred Talents Programs of the Chinese Academy of Sciences
文摘Optical planar waveguides in Yba+-doped phosphate glasses are fabricated by implanting triple-energy helium ions. The guiding modes and the near-field intensity distribution are measured by using the prism-coupling method and the end-face coupling setup with a He Ne laser at 633 nm The intensity calculation method (ICM) is used to reconstruct the refractive index profile of the waveguide. The absorption and the fluorescence investigations reveal that the glass bulk features are well preserved in the active volumes of the waveguides, suggesting the fabricated structures for possible applications as waveguide lasers.
基金Project supported by the National Natural Science Foundation of China(Grant No.61172044)the Natural Science Foundation of Hebei Province,China(Grant No.F2014501150)
文摘A novel nanolaser structure based on a hybrid plasmonic waveguide is proposed and investigated. The coupling between the metal nanowire and the high-index semiconductor nanowire with optical gain leads to a strong field enhancement in the air gap region and low propagation loss, which enables the realization of lasing at the deep subwavelength scale.By optimizing the geometric parameters of the structure, a minimal lasing threshold is achieved while maintaining the capacity of ultra-deep subwavelength mode confinement. Compared with the previous coupled nanowire pair based hybrid plasmonic structure, a lower threshold can be obtained with the same geometric parameters. The proposed nanolaser can be integrated into a miniature chip as a nanoscale light source and has the potential to be widely used in optical communication and optical sensing technology.
文摘The multimodal admittance method and its improvement are presented to deal with various aspects in underwater acoustics,mostly for the sound propagation in inhomogeneous waveguides with sound-speed profiles,arbitrary-shaped liquid-like scatterers,and range-dependent environments.In all cases,the propagation problem governed by the Helmholtz equation is transformed into initial value problems of two coupled first-order evolution equations with respect to the modal components of field quantities(sound pressure and its derivative),by projecting the Helmholtz equation on a constructed orthogonal and complete local basis.The admittance matrix,which is the modal representation of Direchlet-to-Neumann operator,is introduced to compute the first-order evolution equations with no numerical instability caused by evanescent modes.The fourth-order Magnus scheme is used for the numerical integration of differential equations in the numerical implementation.The numerical experiments of sound field in underwater inhomogeneous waveguides generated by point sources are performed.Besides,the numerical results computed by simulation software COMSOL Multiphysics are given to validate the correction of the multimodal admittance method.It is shown that the multimodal admittance method is an efficient and stable numerical method to solve the wave propagation problem in inhomogeneous underwater waveguides with sound-speed profiles,liquid-like scatterers,and range-dependent environments.The extension of the method to more complicated waveguides such as horizontally stratified waveguides is available.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61421062 and 61520106004)the Microsoft Research Fund of Asia
文摘In this paper, we consider the inverse scattering problem of reconstructing a bounded obstacle in a three-dimensional planar waveguide from the scattered near-field data measured on a finite cylindrical surface containing the obstacle and corresponding to infinitely many incident point sources also placed on the measurement surface. The obstacle is allowed to be an impenetrable scatterer or a penetrable scatterer. We establish the validity of the factorization method with the nearfield data to characterize the obstacle in the planar waveguide by constructing an outgoing-to-incoming operator which is an integral operator defined on the measurement surface with the kernel given in terms of an infinite series.
文摘A high efficiency grating coupler between single-mode fiber and silicon-on-insulator waveguide is designed by a formula method.Over 78.5%coupling efficiency(>-1.05 dB)with 3 dB bandwidth about 50 nm for one grating coupler is obtained experimentally and this result is the highest one as far as we know.This grating coupler is CMOS compatible which needs only one etch-step and is designed for a standard SOI chip without any Bragg reflector or bottom reflector.
基金We are grateful for financial supports from National Natural Science Foundation of China(NSFC)(Grants No.61575097 and 11704201)National Natural Science Foundation of Tianjin City(NSFTJ)(17JCQNJC01600 and 19JCZDJC32700)the Fundamental Research Funds for the Central Universities.
文摘We report on the fabrication of circular cladding waveguides with cross-section diameters of 60−120μm in Pr:YAG crystal by applying femtosecond laser inscription.The fabricated waveguides present 2D guidance on the cross-section and fairly low propagation losses.Multiple high-order guiding modes are observed in waveguides with different diameters.Corresponding simulation results reveal the origin of a specific kind of guiding modes.Confocal micro-Raman(μ-Raman)experiments demonstrate the modification effects in femtosecond laser affected areas and ascertain the refractive index induced guiding mechanism.In addition,luminescence emission properties of Pr3+ions at waveguide volume are well preserved during the femtosecond laser inscription process,which may result in a potential high-power visible waveguide laser.
基金Supported by the National Natural Science Foundation of China under Grant No 11105001the Anhui Provincial Natural Science Foundation under Grant Nos 1408085QA22 and 1608085MA09
文摘The single photon scattering properties in a pair of waveguides coupled by a whispering-gallery resonator in- teracting with a semiconductor quantum dot are investigated theoretically. The two waveguides support four possible ports for an incident single photon. The quantum dot is considered a V-type system. The incident direction-dependent single photon scattering properties are studied and equal-output probability from the four ports for a single photon incident is discussed. The influences of backscattering between the two modes of the whispering-gallery resonator for incident direction-dependent single photon scattering properties are also pre- sented.
文摘With the help of the effective refractive index method we have numerically analyzed a multilayer planar waveguide structure and calculated the propagation constants, confinement factors, and transverse electric (TE) modes. A five-layer waveguide model has been provided to analyze the electro-magne tic wave propagation process. The analysis method has been applied to the 980 nm laser with active layer of GaInAs/GaInAsP strained quantum wells, GaInAsP confinement layers and GaInP cap layers. By changing the thickness of confinement layers, we obtained confinement factor as high as 95% with higher TE modes TE1 and TE2. The results are in good agreement with the experiment by A. Al-Muhanna et al. and give the new idea to enhance output power of semiconductor lasers. The analysis method can also be extended to any other slab multilayer waveguide structures, and the results are useful to the fabrication of optic-electronic devices.
文摘A simple solution for a multilayer metallic optical waveguide by transforming it intoan equivalent three-layer slab waveguide is presented. The dispersion relation of the equivalentthree-layer slab waveguide is solved by using a simple iterative formula. This method itself isexact and can approach any accuracy desired. Moreover, the numerical results for four-layer andfive-layer structures show that the second-order solution is also accurate enough. It is simple andhas the same form of expressions for TE and TM modes and for different layer structures.
基金Project supported by the National Natural Science Foundation of China (Grant No 60671030)the Scientific Research Foundation for the Introduced Talents, UESTC (Grant No Y02002010501022)
文摘Applying the spinor representation of the electromagnetic field, this paper present a quantum-mechanical description of waveguides. As an example of application, a potential qubit generated by photon tunnelling is discussed.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.10174024 and 10474025)
文摘We establish the superfluidity theory of coherent light in waveguides made of nonlinear polar crystals.It is found that the pairing state of photons in a nonlinear polar crystal is the photonic superfluid state.The photon-photon interaction potential is an attractive effective interaction by exchange of virtual optical phonons.In the traveling-wave pairing state of photons,the photon number is conserved,which is similar to the Bose-Einstein condensation(BEC) state of photons.In analogy to the BCS-BEC crossover theory of superconductivity,we derive a set of coupled order parameter and number equations,which determine the solution of the traveling-wave superfluid state of photons.This solution gives the critical velocity of light in a self-focusing nonlinear waveguide.The most important property of the photonic superfluid state is that the system of photon pairs evolves without scattering attenuations.
基金Project supported by the "985 project" (Grant Nos.98503-008006 and 98503-008017)the "211 project" of Ministry of Education of Chinathe Fundamental Research Funds for the Central Universities of China
文摘On the basis of two-dimensional amorphous photonic materials, we have designed a novel waveguide by inserting thinner cylindrical inclusions in the centre of basic hexagonal units of the amorphous structure along a given path. This waveguide in amorphous structure is similar to the coupled resonator optical waveguides in periodic photonic crystals. The transmission of this waveguide for S-polarized waves is investigated by a multiple-scattering method. Compared with the conventional waveguide by removing a line of cells from amorphous photonic materials, the guiding properties of this waveguide, including the transmissivity and bandwidth, are improved significantly. Then we study the effect of various types of positional disorder on the functionality of this device. Our results show that the waveguide performance is quite sensitive to the disorder located on the boundary layer of the waveguide, but robust against the disorder in the other area in amorphous structure except the waveguide border. This disorder effect in amorphous photonic materials is similar to the case in periodic photonic crystals.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61575129 and 11375105the Postdoctoral Science Foundation of China under Grant No 2016M602511+1 种基金the Shenzhen Science and Technology Planning under Grant No JCYJ20160422142912923the State Key Laboratory of Nuclear Physics and Technology,Peking University
文摘We report on the fabrication of the lO-mm-long lithium niobate ridge waveguide and its supercontinuum gen- eration at near-visible wavelengths (around 800hm). The waveguides are fabricated by a combination of MeV copper ion implantation followed by wet etching in a proton exchanged lithium niobate planar waveguide. Using a mode-locked Ti:sapphire laser with a central wavelength of 800nm, the generated broadest supereontinuum through the ridge waveguides spans 302 nm (at -30 dB points), from 693 to 995 nm. Temporal coherence proper- ties of the supercontinuum are experimentally studied by a Michelson interferometer and the coherence length of the broadest supercontinuum is measured to be 5.2 μm. Our results offer potential for a compact and integrated supercontinuum source for applications including bio-imaging, spectroscopy and optical communication.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11204170 and 61108010)the Shanghai Municipal Commission of Science and Technology,China(Grant No.16ZR1411600)
文摘The graphene-based double-barrier waveguides induced by electric field have been investigated. The guided modes can only exist in the case of Klein tunneling, and the fundamental mode is absent. The guided modes in the single-barrier waveguide split into symmetric and antisymmetric modes with different incident angles in the double-barrier waveguide. The phase difference between electron states and hole states is also discussed. The phase difference for the two splitting modes is close to each other and increases with the order of guided modes. These phenomena can be helpful for the potential applications in graphene-based optoelectronic devices.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11405041 and 61177084)the Nanjing University of Posts and Telecommunications Scientific Foundation(NUPTSF),China(Grant No.NY214159)the RCOCET,China(Grant No.ZSF0401)
文摘A Nd:CLNGG waveguide structure operated at wavelengths of both 632.8 nm and 1539 nm was demonstrated for the first time to our knowledge, which was produced by the 480-keV H+ ion implantation with a dose of 1.0× 10^17 protons/cm2, Its propagating modes at 632.8 nm and 1539 nm were measured by the well-known prism coupling technique. The refractive index profile at either 632.8-nm wavelength or 1539-nm wavelength was optical barrier type in the proton-implanted Nd:CLNGG crystal optical waveguide, which was calculated by using the reflectivity calculation method. The near-field light intensity distributions were also simulated by the finite-difference beam propagation method in the visible and nearinfrared bands.