Controlling the distribution of solar spectrum in different bands would boost the energy harvesting efficiency and optimize the energy dispatchability.1D photonic crystal with intrinsic optical band gap can be used to...Controlling the distribution of solar spectrum in different bands would boost the energy harvesting efficiency and optimize the energy dispatchability.1D photonic crystal with intrinsic optical band gap can be used to split the solar spectrum for hybrid photovoltaic/thermal solar applications.Here,we designed an efficient solar spectrum optical filter based on a cermet layer,Si/SiO_(2)1D photonic crystal,and top heterostructure layer.Compared with 1D photonic crystal structure,the 1D photonic crystal heterostructure with top YSZ layer can realize the reflectance of greater than 92%in PV band and the low average reflectance in two thermal bands by tuning the effective impedance of multilayer films.The enhanced reflectance in PV band results from the huge mismatching of impedance between free space and the heterostructure structure.The top dielectric layer can also be extended to other oxides.展开更多
The polymer waveguide optical biosensor based on the Mach-Zehnder interferometer （MZI） by using spectral splitting effect is investigated. The MZI based biosensor has two unequal width sensing arms. With the differe...The polymer waveguide optical biosensor based on the Mach-Zehnder interferometer （MZI） by using spectral splitting effect is investigated. The MZI based biosensor has two unequal width sensing arms. With the different mode dispersion responses of the two-arm waveguides to the cladding refractive index change, the spectral splitting effect of the output interference spectrum is obtained, inducing a very high sensitivity. The influence of the different mode dispersions between the two-arm waveguides on the spectral splitting characteristic is analyzed. By choosing different lengths of the two unequal width sensing arms, the initial dip wavelength of the interference spectrum and the spectral splitting range can be controlled flexibly. The polymer waveguide optical biosensor is designed, and its sensing property is analyzed. The results show that the sensitivity of the polymer waveguide optical biosensor by using spectral splitting effect is as high as 10^4nm/RIU, with an improvement of 2-3 orders of magnitude compared with the slot waveguide based microring biosensor.展开更多
Conventional flat-plate photovoltaic-thermal(PV-T)collectors generate electricity and heat simultaneously;however,the outlet temperature of the latter is typically below 60℃,limiting their widespread application.The ...Conventional flat-plate photovoltaic-thermal(PV-T)collectors generate electricity and heat simultaneously;however,the outlet temperature of the latter is typically below 60℃,limiting their widespread application.The use of optical concentration can enable higher-temperature heat to be generated,but this can also lead to a rise in the operating temperature of the PV cells in the collector and,in turn,to a deterioration in their electrical performance.To overcome this challenge,an optical spectral-splitting filter that absorbs the infrared and transmits the visible portion of the solar spectrum can be used,such that wavelengths below the bandgap are sent to the cells for electricity generation,while those above it are sent to a thermally decoupled absorber for the generation of heat at a temperature that is considerably higher than that of the cells.In this study,a triangular primary PV-T channel,wherein the primary heat transfer fluid(water)flows,is integrated into a parabolic trough concentrator of geometrical concentration ratio~10,while a secondary liquid filter(water,AgSiO_(2)-eg or Therminol-66)is introduced for spectral splitting.Optical,electrical and thermal-fluid(sub-)models are developed and coupled to study the performance of this collector.Each sub-model is individually checked against results taken from the literature with maximum deviations under 10%.Subsequently,the optical and electrical models are coupled with a 3-D thermal-fluid CFD model(using COMSOL Multiphysics 6.1)to predict the electrical and thermal performance of the collector.Results show that when water is used as the optical filter,the maximum overall thermal(filter channel plus primary channel)and electrical efficiencies of the collector reach~45%and 15%,respectively.A comparison between water,AgSiO_(2)-eg and Therminol-66 reveals that AgSiO_(2)-eg improves the thermal efficiency of the filter channel by~25%(absolute)compared to Therminol-66 and water,however,this improvement–which arises from the thermal performance of the filter–comes at an expense of a~5%electrical efficiency loss.展开更多
Two-dimensional （2D） closed-cavity single quantum well （SQW） and multiple quantum well （MQW） structures are proposed based on the traditional 2D open-cavity SQW structures of photonic crystals. The numerical cal...Two-dimensional （2D） closed-cavity single quantum well （SQW） and multiple quantum well （MQW） structures are proposed based on the traditional 2D open-cavity SQW structures of photonic crystals. The numerical calculation results show that the proposed structures can greatly improve the optical characteristics compared with the traditional structures. It is found that the barrier thickness has a great impact on the optical characteristics of the closed-cavity MQW structures： when the barrier thickness is narrower, each resonant peak which appears in the SQW would split, the number of split times is just equal to the number of wells, and each well in the MQW structures is a travelling-wave-well, similar to the well in the open-cavity SQW structures; when the barrier thickness is wider, there is no effect of spectral splitting, and each well in the MQW structures is a standing-wave-well, just like the well in the closed-cavity SQW. The physical origin of different field distributions and the effect of the spectral splitting are provided.展开更多
The anomalous non-Hermitian dynamical phenomenon with the non-Hermitian skin effect(NHSE)attracts wide attention due to its novel physics and promising applications.Here,we propose a new type of non-unitary discrete-t...The anomalous non-Hermitian dynamical phenomenon with the non-Hermitian skin effect(NHSE)attracts wide attention due to its novel physics and promising applications.Here,we propose a new type of non-unitary discrete-time quantum walk system demonstrating the NHSE and anomalous non-Hermitian dynamical phenomena,including the dynamical chiral phenomenon,the funneling phenomenon on the domain wall,and the anomalous reflection on the phase impurity.Furthermore,we design the quantum circuit experiments of these quantum walk systems and numerically simulate them with quantum noises to verify the robustness of the non-Hermitian dynamical phenomenon on the noisy intermediate-scale quantum(NISQ)devices.Our work paves the way for implementing the non-Hermitian dynamical phenomenon on the quantum circuit.展开更多
By utilizing a Fabry–Perot （FP） nanocavity adjacent to T-shaped gap waveguide ports, spectrally selective filtering is realized. When the wavelength of incident light corresponds to the resonance wavelength of the ...By utilizing a Fabry–Perot （FP） nanocavity adjacent to T-shaped gap waveguide ports, spectrally selective filtering is realized. When the wavelength of incident light corresponds to the resonance wavelength of the FP nanocavity, the surface plasmons are captured inside the nanocavity, and light is highly reflected from this port. The resonance wavelength is determined by using Fabry–Perot resonance condition for the nanocavity. For any desired filtering frequency the dimension of the nanocavity can be tailored. The numerical results are based on the two-dimensional finite difference time domain simulation under a perfectly matched layer absorbing boundary condition. The analytical and simulation results indicate that the proposed structure can be utilized for filtering and splitting applications.展开更多
Selective absorptive nanofluid can pre-absorb certain sunlight wavelength that cannot be used by PV and transmits remaining sunlight to the surface of PV,which can decouple PV from the thermal receiver spatially.In or...Selective absorptive nanofluid can pre-absorb certain sunlight wavelength that cannot be used by PV and transmits remaining sunlight to the surface of PV,which can decouple PV from the thermal receiver spatially.In order to improve the harvesting of electricity and high-temperature thermal nanofluid,it is important to design an optimal optical filter window(transmit sunlight with wavelengths of 732-1067 nm to the surface of the photovoltaic cell and absorb the remaining sunlight).However,designing optimal optical filter is facing following challenges:(1) inherently narrow selective absorptivity property of single nanoparticle;(2) simplified numerical calculation method calculating transmittance;(3) ignoring the shape of the nanoparticle.In this study,the idea of using multiple nanoparticles coupling effect to design an optical filter is proposed,which can superimpose the narrow absorption bandwidth of different nanoparticles to obtain a wide absorption bandwidth of the whole system.In addition,an improved transmission method considering light-matter interaction at air/vessel and liquid/vessel interfaces is adopted to compute the transmittance.The results calculated by improved transmission method are more accurate than widely used traditional Lambert-Beer law,which is verified by experimental test.Furthermore,the effect of nanoparticle shape on spectral transmittance is also investigated,which shows that spiny Ag can approximately extend absorbance from 400 nm to 600 nm compared to nanosphere silver.Finally,the results show that optical filter efficiency of nanofluids with multiple nanoparticles coupling(Ag,spiny Ag,ZnO,ITO) can reached up to 35%.展开更多
The efficient utilization of solar energy can be achieved by coupling photovoltaic(PV) and photothermal(PT) technologies to harness the full spectrum of solar radiation.In this work,a new type of CuO-CoSO_(4) nanoflui...The efficient utilization of solar energy can be achieved by coupling photovoltaic(PV) and photothermal(PT) technologies to harness the full spectrum of solar radiation.In this work,a new type of CuO-CoSO_(4) nanofluid was proposed,and its performance in a photovoltaic/thermal(PV/T) system was studied.CuO-CoSO_(4) nanofluids with different concentrations were prepared by two-step method,and their optical properties and stability were characterized.The experimental results show that the 50 mg/L CuO-CoSO4nanofluid has high transmittance in the ideal optical window of silicon cells(650-1040 nm),with an average transmittance of 67.58%,and higher absorptivity in the short waveband and infrared bands(280-650 nm and 1040-2500 nm),with an average absorptance of 68.52%,effectively realizing spectrum splitting.By establishing a performance analysis model for the nanofluid-based spectral splitting PV/T system,the electrical efficiency,thermal efficiency and total efficiency of the system at different concentrations were calculated,and the Merit function(MF) was introduced to comprehensively evaluate the system performance.The results show that the CuO-CoSO_(4) nanofluid has the best spectral splitting performance when the CuO concentration is 50 mg/L.The system achieves an electrical efficiency of 14.46%,a thermal efficiency of 37.60%,and a system efficiency of 52.06%.The MF value reaches 1.2851,indicating a 28.51% improvement over traditional PV systems.This study provides a theoretical basis for the practical application and optimization of nanofluids in PV/T systems.展开更多
In this paper, three numerical schemes with high accuracy for the coupled Schrodinger equations are studied. The conserwtive properties of the schemes are obtained and the plane wave solution is analysised. The split ...In this paper, three numerical schemes with high accuracy for the coupled Schrodinger equations are studied. The conserwtive properties of the schemes are obtained and the plane wave solution is analysised. The split step Runge-Kutta scheme is conditionally stable by linearized analyzed. The split step compact scheme and the split step spectral method are unconditionally stable. The trunction error of the schemes are discussed. The fusion of two solitions colliding with different β is shown in the figures. The numerical experments demonstrate that our algorithms are effective and reliable.展开更多
基金the National Natural Science Foundation of China(51871081,11674078 and 51971081)the Natural Science Foundation of Guangdong Province of China(2018A0303130033)+1 种基金Shenzhen Fundamental Research Project(JCYJ20170811155832192)Natural Scientific Research Innovation Foundation in Harbin Institute of Technology(HIT.NSRIF.2020060).
文摘Controlling the distribution of solar spectrum in different bands would boost the energy harvesting efficiency and optimize the energy dispatchability.1D photonic crystal with intrinsic optical band gap can be used to split the solar spectrum for hybrid photovoltaic/thermal solar applications.Here,we designed an efficient solar spectrum optical filter based on a cermet layer,Si/SiO_(2)1D photonic crystal,and top heterostructure layer.Compared with 1D photonic crystal structure,the 1D photonic crystal heterostructure with top YSZ layer can realize the reflectance of greater than 92%in PV band and the low average reflectance in two thermal bands by tuning the effective impedance of multilayer films.The enhanced reflectance in PV band results from the huge mismatching of impedance between free space and the heterostructure structure.The top dielectric layer can also be extended to other oxides.
基金This work was supported in part by the International Science ＆ Technology Cooperation Program of China （No. 2014DFG32590）, National Natural Science Foundation of China （No. 61307040）, National R＆D Program （No. 2012AA040406）, National Research Foundation of China （No. 6140450010305）, Natural Science Foundation of Liaoning Province （No. 2014020002）, and Fundamental Research Funds for the Central Universities （DUT 15ZD231 and DUT2015TD47）.
文摘The polymer waveguide optical biosensor based on the Mach-Zehnder interferometer （MZI） by using spectral splitting effect is investigated. The MZI based biosensor has two unequal width sensing arms. With the different mode dispersion responses of the two-arm waveguides to the cladding refractive index change, the spectral splitting effect of the output interference spectrum is obtained, inducing a very high sensitivity. The influence of the different mode dispersions between the two-arm waveguides on the spectral splitting characteristic is analyzed. By choosing different lengths of the two unequal width sensing arms, the initial dip wavelength of the interference spectrum and the spectral splitting range can be controlled flexibly. The polymer waveguide optical biosensor is designed, and its sensing property is analyzed. The results show that the sensitivity of the polymer waveguide optical biosensor by using spectral splitting effect is as high as 10^4nm/RIU, with an improvement of 2-3 orders of magnitude compared with the slot waveguide based microring biosensor.
基金supported by the UK Engineering and Physical Sciences Research Council(EPSRC)(Grant No.EP/R045518/1)the Royal Society under an International Collaboration Award 2020(Grant No.ICA\R1\201302)+2 种基金UK company Solar Flow Ltd.This work has also been funded by the European Union under the SPECTRUM project(Grant Agreement No.101172891)support for this research was provided by Tecnologico de Monterrey Challenge-Based Research Funding Programsupporting this publication can be obtained on request from cep-laboratory@imperial.ac.uk.For the purpose of Open Access,the authors have applied a CC BY public copyright license to any Author Accepted Manuscript version arising from this submission.
文摘Conventional flat-plate photovoltaic-thermal(PV-T)collectors generate electricity and heat simultaneously;however,the outlet temperature of the latter is typically below 60℃,limiting their widespread application.The use of optical concentration can enable higher-temperature heat to be generated,but this can also lead to a rise in the operating temperature of the PV cells in the collector and,in turn,to a deterioration in their electrical performance.To overcome this challenge,an optical spectral-splitting filter that absorbs the infrared and transmits the visible portion of the solar spectrum can be used,such that wavelengths below the bandgap are sent to the cells for electricity generation,while those above it are sent to a thermally decoupled absorber for the generation of heat at a temperature that is considerably higher than that of the cells.In this study,a triangular primary PV-T channel,wherein the primary heat transfer fluid(water)flows,is integrated into a parabolic trough concentrator of geometrical concentration ratio~10,while a secondary liquid filter(water,AgSiO_(2)-eg or Therminol-66)is introduced for spectral splitting.Optical,electrical and thermal-fluid(sub-)models are developed and coupled to study the performance of this collector.Each sub-model is individually checked against results taken from the literature with maximum deviations under 10%.Subsequently,the optical and electrical models are coupled with a 3-D thermal-fluid CFD model(using COMSOL Multiphysics 6.1)to predict the electrical and thermal performance of the collector.Results show that when water is used as the optical filter,the maximum overall thermal(filter channel plus primary channel)and electrical efficiencies of the collector reach~45%and 15%,respectively.A comparison between water,AgSiO_(2)-eg and Therminol-66 reveals that AgSiO_(2)-eg improves the thermal efficiency of the filter channel by~25%(absolute)compared to Therminol-66 and water,however,this improvement–which arises from the thermal performance of the filter–comes at an expense of a~5%electrical efficiency loss.
基金supported by the National Natural Science Foundation of China (Grant Nos 60577006 and 50774034)the Hunan Provincial Science Foundation of China (Grant No 06JJ20005)
文摘Two-dimensional （2D） closed-cavity single quantum well （SQW） and multiple quantum well （MQW） structures are proposed based on the traditional 2D open-cavity SQW structures of photonic crystals. The numerical calculation results show that the proposed structures can greatly improve the optical characteristics compared with the traditional structures. It is found that the barrier thickness has a great impact on the optical characteristics of the closed-cavity MQW structures： when the barrier thickness is narrower, each resonant peak which appears in the SQW would split, the number of split times is just equal to the number of wells, and each well in the MQW structures is a travelling-wave-well, similar to the well in the open-cavity SQW structures; when the barrier thickness is wider, there is no effect of spectral splitting, and each well in the MQW structures is a standing-wave-well, just like the well in the closed-cavity SQW. The physical origin of different field distributions and the effect of the spectral splitting are provided.
基金Project supported by the National Key R&D Program of China (Grant No. 2022YFA1403901)the National Natural Science Foundation of China (Grant No. NSFC-11888101)+2 种基金the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB28000000)New Cornerstone Investigator Programsupported by the fellowship of China National Postdoctoral Program for Innovative Talents (Grant No. BX2021300)
文摘The anomalous non-Hermitian dynamical phenomenon with the non-Hermitian skin effect(NHSE)attracts wide attention due to its novel physics and promising applications.Here,we propose a new type of non-unitary discrete-time quantum walk system demonstrating the NHSE and anomalous non-Hermitian dynamical phenomena,including the dynamical chiral phenomenon,the funneling phenomenon on the domain wall,and the anomalous reflection on the phase impurity.Furthermore,we design the quantum circuit experiments of these quantum walk systems and numerically simulate them with quantum noises to verify the robustness of the non-Hermitian dynamical phenomenon on the noisy intermediate-scale quantum(NISQ)devices.Our work paves the way for implementing the non-Hermitian dynamical phenomenon on the quantum circuit.
基金Project supported by the National Key Basic Research Program of China (Grant No. 2013CB328702)
文摘By utilizing a Fabry–Perot （FP） nanocavity adjacent to T-shaped gap waveguide ports, spectrally selective filtering is realized. When the wavelength of incident light corresponds to the resonance wavelength of the FP nanocavity, the surface plasmons are captured inside the nanocavity, and light is highly reflected from this port. The resonance wavelength is determined by using Fabry–Perot resonance condition for the nanocavity. For any desired filtering frequency the dimension of the nanocavity can be tailored. The numerical results are based on the two-dimensional finite difference time domain simulation under a perfectly matched layer absorbing boundary condition. The analytical and simulation results indicate that the proposed structure can be utilized for filtering and splitting applications.
基金supported by the National Natural Science Foundation of China (Grant No.52076064)the Taishan Scholars of Shandong Province (tsqn 201812105)+1 种基金China Scholarship Council (202106120157)CSC grant for LIANG Huaxu's scholarship of research visiting at Nanyang Technological University, Singapore。
文摘Selective absorptive nanofluid can pre-absorb certain sunlight wavelength that cannot be used by PV and transmits remaining sunlight to the surface of PV,which can decouple PV from the thermal receiver spatially.In order to improve the harvesting of electricity and high-temperature thermal nanofluid,it is important to design an optimal optical filter window(transmit sunlight with wavelengths of 732-1067 nm to the surface of the photovoltaic cell and absorb the remaining sunlight).However,designing optimal optical filter is facing following challenges:(1) inherently narrow selective absorptivity property of single nanoparticle;(2) simplified numerical calculation method calculating transmittance;(3) ignoring the shape of the nanoparticle.In this study,the idea of using multiple nanoparticles coupling effect to design an optical filter is proposed,which can superimpose the narrow absorption bandwidth of different nanoparticles to obtain a wide absorption bandwidth of the whole system.In addition,an improved transmission method considering light-matter interaction at air/vessel and liquid/vessel interfaces is adopted to compute the transmittance.The results calculated by improved transmission method are more accurate than widely used traditional Lambert-Beer law,which is verified by experimental test.Furthermore,the effect of nanoparticle shape on spectral transmittance is also investigated,which shows that spiny Ag can approximately extend absorbance from 400 nm to 600 nm compared to nanosphere silver.Finally,the results show that optical filter efficiency of nanofluids with multiple nanoparticles coupling(Ag,spiny Ag,ZnO,ITO) can reached up to 35%.
基金supported by the Natural Science Foundation of Zhejiang Province(No.LZ25E060001)Fundamental Research Funds for the Central Universities(No.2022ZFJH04).
文摘The efficient utilization of solar energy can be achieved by coupling photovoltaic(PV) and photothermal(PT) technologies to harness the full spectrum of solar radiation.In this work,a new type of CuO-CoSO_(4) nanofluid was proposed,and its performance in a photovoltaic/thermal(PV/T) system was studied.CuO-CoSO_(4) nanofluids with different concentrations were prepared by two-step method,and their optical properties and stability were characterized.The experimental results show that the 50 mg/L CuO-CoSO4nanofluid has high transmittance in the ideal optical window of silicon cells(650-1040 nm),with an average transmittance of 67.58%,and higher absorptivity in the short waveband and infrared bands(280-650 nm and 1040-2500 nm),with an average absorptance of 68.52%,effectively realizing spectrum splitting.By establishing a performance analysis model for the nanofluid-based spectral splitting PV/T system,the electrical efficiency,thermal efficiency and total efficiency of the system at different concentrations were calculated,and the Merit function(MF) was introduced to comprehensively evaluate the system performance.The results show that the CuO-CoSO_(4) nanofluid has the best spectral splitting performance when the CuO concentration is 50 mg/L.The system achieves an electrical efficiency of 14.46%,a thermal efficiency of 37.60%,and a system efficiency of 52.06%.The MF value reaches 1.2851,indicating a 28.51% improvement over traditional PV systems.This study provides a theoretical basis for the practical application and optimization of nanofluids in PV/T systems.
文摘In this paper, three numerical schemes with high accuracy for the coupled Schrodinger equations are studied. The conserwtive properties of the schemes are obtained and the plane wave solution is analysised. The split step Runge-Kutta scheme is conditionally stable by linearized analyzed. The split step compact scheme and the split step spectral method are unconditionally stable. The trunction error of the schemes are discussed. The fusion of two solitions colliding with different β is shown in the figures. The numerical experments demonstrate that our algorithms are effective and reliable.
