Nonlinear dielectric metasurfaces provide a promising approach to control and manipulate frequency conversion optical processes at the nanoscale,thus facilitating both advances in fundamental research and the developm...Nonlinear dielectric metasurfaces provide a promising approach to control and manipulate frequency conversion optical processes at the nanoscale,thus facilitating both advances in fundamental research and the development of new practical applications in photonics,lasing,and sensing.Here,we employ symmetry-broken metasurfaces made of centrosymmetric amorphous silicon for resonantly enhanced second-and third-order nonlinear optical response.Exploiting the rich physics of optical quasi-bound states in the continuum and guided mode resonances,we comprehensively study through rigorous numerical calculations the relative contribution of surface and bulk effects to second-harmonic generation(SHG)and the bulk contribution to third-harmonic generation(THG) from the meta-atoms.Next,we experimentally achieve optical resonances with high quality factors,which greatly boosts light-matter interaction,resulting in about 550 times SHG enhancement and nearly 5000-fold increase of THG.A good agreement between theoretical predictions and experimental measurements is observed.To gain deeper insights into the physics of the investigated nonlinear optical processes,we further numerically study the relation between nonlinear emission and the structural asymmetry of the metasurface and reveal that the generated harmonic signals arising from linear sharp resonances are highly dependent on the asymmetry of the meta-atoms.Our work suggests a fruitful strategy to enhance the harmonic generation and effectively control different orders of harmonics in all-dielectric metasurfaces,enabling the development of efficient active photonic nanodevices.展开更多
Lithium niobate has received interest in nonlinear frequency conversion due to its wide transparency window,from ultraviolet to mid-infrared spectral regions,and large second-order nonlinear susceptibility.However,its...Lithium niobate has received interest in nonlinear frequency conversion due to its wide transparency window,from ultraviolet to mid-infrared spectral regions,and large second-order nonlinear susceptibility.However,its nanostructure is generally difficult to etch,resulting in low-Q resonance and lossy nanostructures for second harmonic generation.By applying the concept of bound states in the continuum,we performed theoretical and experimental investigations on high-Q resonant etchless thin-film lithium niobate with Si O_(2) nanostructures on top for highly efficient second harmonic generation.In the fabricated nanostructured devices,a resonance with a Q factor of 980 leads to the strong enhancement of second harmonic generation by over 1500 times compared with that in unpatterned lithium niobate thin film.Although the pump slightly deviates from central resonance,an absolute conversion efficiency of 6.87×10^(-7) can be achieved with the fundamental pump peak intensity of 44.65 MW/cm^(2),thus contributing to the normalized conversion efficiency of 1.54×10^(-5)cm^(2)/GW.Our work establishes an etchless lithium niobate device for various applications,such as integrated nonlinear nanophotonics,terahertz frequency generation,and quantum information processing.展开更多
The main aim of this paper is to investigate the different types of soliton molecule solutions of the second extend(3+1)-dimensional Jimbo-Miwa equation in a fluid.Four different localized waves:line solitons,breather...The main aim of this paper is to investigate the different types of soliton molecule solutions of the second extend(3+1)-dimensional Jimbo-Miwa equation in a fluid.Four different localized waves:line solitons,breather waves,lump solutions and resonance Y-type solutions are obtained by the Hirota bilinear method directly.Furthermore,the molecule solutions consisting of only line waves,breathers or lump waves are generated by combining velocity resonance condition and long wave limit method.Also,the molecule solutions such as line-breather molecule,lump-line molecule,lump-breather molecule,etc.consisting of different waves are derived.Meanwhile,higher-order molecule solutions composed of only line waves are acquired.展开更多
The plasmon-enhanced second-harmonic generation(SHG)of Au nanorods(NRs),Au-Ag NRs,and asymmetric Au@CdSe heterorods are comparatively investigated.The Au@CdSe tip-and side-heterorods are synthesized by precisely contr...The plasmon-enhanced second-harmonic generation(SHG)of Au nanorods(NRs),Au-Ag NRs,and asymmetric Au@CdSe heterorods are comparatively investigated.The Au@CdSe tip-and side-heterorods are synthesized by precisely controlling the concentration of Cd2+precursor,and the plasmon resonances can be well tuned simultaneously.The SHG of asymmetric Au@CdSe heterorods has been greatly enhanced with up to 617.7-fold enhancement compared with the Au NRs because of the asymmetric morphology and local field enhancement.Moreover,the harmonic energy transfer induced by the local interband transition of Au has also been demonstrated by the excitation-wavelengthdependent SHG in the Au NRs and Au@CdSe side-heterorods,while it is negligible in the Au-Ag NRs and Au@CdSe tipheterorods because of the presence of Ag.The plasmon-enhanced SHG of asymmetric Au@CdSe heterorods enables potential applications ranging from sensing to biological spectroscopy.展开更多
Dependence of the periodically poled nonlinear-optical lithium niobate (PPLN) crystal temperature on laser power in the course of laser frequency conversion was measured using piezoelectric resonance. Crystal’s tempe...Dependence of the periodically poled nonlinear-optical lithium niobate (PPLN) crystal temperature on laser power in the course of laser frequency conversion was measured using piezoelectric resonance. Crystal’s temperature tuning curves are precisely measured using concept of the equivalent temperature. Both optical absorption and heat transfer coefficients of the crystal are measured employing kinetics of the crystal equivalent temperature.展开更多
The transition metal dichalcogenides(TMD)monolayers have shown strong second-harmonic generation(SHG)ow-ing to their lack of inversion symmetry.These ultrathin layers then serve as the frequency converters that can be...The transition metal dichalcogenides(TMD)monolayers have shown strong second-harmonic generation(SHG)ow-ing to their lack of inversion symmetry.These ultrathin layers then serve as the frequency converters that can be intergraded on a chip.Here,taking MoSSe as an example,we report the first detailed experimental study of the SHG of Janus TMD monolayer,in which the transition metal layer is sandwiched by the two distinct chalcogen layers.It is shown that the SHG effectively arises from an in-plane second-harmonic polarization under paraxial focusing and detection.Based on this,the orientation-resolved SHG spectroscopy is realized to readily determine the zigzag and armchair axes of the Janus crystal with an accuracy better than±0.6°.Moreover,the SHG intensity is wavelength-dependent and can be greatly enhanced(~60 times)when the two-photon transition is resonant with the C-exciton state.Our findings uncover the SHG properties of Janus MoSSe monolayer,therefore lay the basis for its integrated frequency-doubling applications.展开更多
The interaction between congo red (CR) and amikacin (AMK) was studied by resonance Rayleigh scattering (RRS), frequency doubling scattering (FDS) and second-order scattering (SOS) combining with absorption spectrum. I...The interaction between congo red (CR) and amikacin (AMK) was studied by resonance Rayleigh scattering (RRS), frequency doubling scattering (FDS) and second-order scattering (SOS) combining with absorption spectrum. In a weak acidic medium, CR combined with AMK to form an ion association complex with the composition ratio of 1∶1 by electrostatic interaction, hydrophobicity and charge transferring effect. As a result, the new spectra of RRS, FDS, and SOS appeared and their intensities were enhanced greatly. The maximum wavelengths of RRS, FDS and SOS were located at 563 nm, 475 nm and 940 nm, and the scattering intensities were proportional to the concentration of AMK. These three methods have very high sensitivities, and the detection limits were 4.0 ng·mL?1 for RRS, 3.6 ng·mL?1 for FDS and 1.9 ng·mL?1 for SOS, respectively. At the same time, the methods have better selectivity. A new method for the determination of trace amounts of AMK with congo red by resonance scattering technique has been developed. The recovery for the determination of AMK in blood serum and urine sample was between 95.5% and 105.5%. In this study, the properties, such as enthalpy of formation, charge distribution and mean polarizability, were calculated by AM1 quantum chemistry method. In addition, the reaction mechanism and the reasons for the enhancement of scattering spectra were discussed.展开更多
Based on the potential theory and perturbation techniques, the problem of second-order sloshing in a three-dimensional tank in combination with surge and sway motions is analyzed. When excitation is applied in both ho...Based on the potential theory and perturbation techniques, the problem of second-order sloshing in a three-dimensional tank in combination with surge and sway motions is analyzed. When excitation is applied in both horizontal directions, the second-order resonance can occur when the sum frequency or the difference frequency of any two excitation components is equal to one of the natural frequencies. The resonance can also occur when the sum or difference frequency of one of the excitation frequencies and one of the natural frequencies is equal to another natural frequency.展开更多
基金supported by the Australian Research Council(Grant No.DP210101292)the International Technology Center Indo-Pacific (ITC IPAC) via Army Research Office (contract FA520923C0023)。
文摘Nonlinear dielectric metasurfaces provide a promising approach to control and manipulate frequency conversion optical processes at the nanoscale,thus facilitating both advances in fundamental research and the development of new practical applications in photonics,lasing,and sensing.Here,we employ symmetry-broken metasurfaces made of centrosymmetric amorphous silicon for resonantly enhanced second-and third-order nonlinear optical response.Exploiting the rich physics of optical quasi-bound states in the continuum and guided mode resonances,we comprehensively study through rigorous numerical calculations the relative contribution of surface and bulk effects to second-harmonic generation(SHG)and the bulk contribution to third-harmonic generation(THG) from the meta-atoms.Next,we experimentally achieve optical resonances with high quality factors,which greatly boosts light-matter interaction,resulting in about 550 times SHG enhancement and nearly 5000-fold increase of THG.A good agreement between theoretical predictions and experimental measurements is observed.To gain deeper insights into the physics of the investigated nonlinear optical processes,we further numerically study the relation between nonlinear emission and the structural asymmetry of the metasurface and reveal that the generated harmonic signals arising from linear sharp resonances are highly dependent on the asymmetry of the meta-atoms.Our work suggests a fruitful strategy to enhance the harmonic generation and effectively control different orders of harmonics in all-dielectric metasurfaces,enabling the development of efficient active photonic nanodevices.
基金supported by the National Natural Science Foundation of China (Grant Nos. 61775084, and 62075088)the National Safety Academic Fund (Grant No. U2030103)+2 种基金the Natural Science Foundation of Guangdong Province (Grant Nos. 2020A1515010791, and 2021A0505030036)the Open Fund of Guangdong Provincial Key Laboratory of Information Photonics Technology of Guangdong University of Technology (Grant No. GKPT20-03)the Fundamental Research Funds for the Central Universities (Grant Nos. 21622107, and 21622403)。
文摘Lithium niobate has received interest in nonlinear frequency conversion due to its wide transparency window,from ultraviolet to mid-infrared spectral regions,and large second-order nonlinear susceptibility.However,its nanostructure is generally difficult to etch,resulting in low-Q resonance and lossy nanostructures for second harmonic generation.By applying the concept of bound states in the continuum,we performed theoretical and experimental investigations on high-Q resonant etchless thin-film lithium niobate with Si O_(2) nanostructures on top for highly efficient second harmonic generation.In the fabricated nanostructured devices,a resonance with a Q factor of 980 leads to the strong enhancement of second harmonic generation by over 1500 times compared with that in unpatterned lithium niobate thin film.Although the pump slightly deviates from central resonance,an absolute conversion efficiency of 6.87×10^(-7) can be achieved with the fundamental pump peak intensity of 44.65 MW/cm^(2),thus contributing to the normalized conversion efficiency of 1.54×10^(-5)cm^(2)/GW.Our work establishes an etchless lithium niobate device for various applications,such as integrated nonlinear nanophotonics,terahertz frequency generation,and quantum information processing.
文摘The main aim of this paper is to investigate the different types of soliton molecule solutions of the second extend(3+1)-dimensional Jimbo-Miwa equation in a fluid.Four different localized waves:line solitons,breather waves,lump solutions and resonance Y-type solutions are obtained by the Hirota bilinear method directly.Furthermore,the molecule solutions consisting of only line waves,breathers or lump waves are generated by combining velocity resonance condition and long wave limit method.Also,the molecule solutions such as line-breather molecule,lump-line molecule,lump-breather molecule,etc.consisting of different waves are derived.Meanwhile,higher-order molecule solutions composed of only line waves are acquired.
基金supported by the National Key R&D Program of China(2017YFA0303402)the National Natural Science Foundation of China(11874293,91750113,11674254 and 11504105)。
文摘The plasmon-enhanced second-harmonic generation(SHG)of Au nanorods(NRs),Au-Ag NRs,and asymmetric Au@CdSe heterorods are comparatively investigated.The Au@CdSe tip-and side-heterorods are synthesized by precisely controlling the concentration of Cd2+precursor,and the plasmon resonances can be well tuned simultaneously.The SHG of asymmetric Au@CdSe heterorods has been greatly enhanced with up to 617.7-fold enhancement compared with the Au NRs because of the asymmetric morphology and local field enhancement.Moreover,the harmonic energy transfer induced by the local interband transition of Au has also been demonstrated by the excitation-wavelengthdependent SHG in the Au NRs and Au@CdSe side-heterorods,while it is negligible in the Au-Ag NRs and Au@CdSe tipheterorods because of the presence of Ag.The plasmon-enhanced SHG of asymmetric Au@CdSe heterorods enables potential applications ranging from sensing to biological spectroscopy.
文摘Dependence of the periodically poled nonlinear-optical lithium niobate (PPLN) crystal temperature on laser power in the course of laser frequency conversion was measured using piezoelectric resonance. Crystal’s temperature tuning curves are precisely measured using concept of the equivalent temperature. Both optical absorption and heat transfer coefficients of the crystal are measured employing kinetics of the crystal equivalent temperature.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.61888102,51771224,and 62175253)the National Key R&D Program of China(Grant Nos.2018YFA0305803 and 2019YFA0308501)+4 种基金the Chinese Academy of Sciences(Grant Nos.XDB33030100 and XDB30010000)J.S.and X.L.thank the supports from the National Natural Science Foundation of China(Grant Nos.20173025,22073022,and 11874130)the National Key R&D Program of China(Grant No.2017YFA0205004)the Chinese Academy of Sciences(Grant Nos.XDB3600000 and Y950291)the DNL Cooperation Fund(Grant No.DNL202016).
文摘The transition metal dichalcogenides(TMD)monolayers have shown strong second-harmonic generation(SHG)ow-ing to their lack of inversion symmetry.These ultrathin layers then serve as the frequency converters that can be intergraded on a chip.Here,taking MoSSe as an example,we report the first detailed experimental study of the SHG of Janus TMD monolayer,in which the transition metal layer is sandwiched by the two distinct chalcogen layers.It is shown that the SHG effectively arises from an in-plane second-harmonic polarization under paraxial focusing and detection.Based on this,the orientation-resolved SHG spectroscopy is realized to readily determine the zigzag and armchair axes of the Janus crystal with an accuracy better than±0.6°.Moreover,the SHG intensity is wavelength-dependent and can be greatly enhanced(~60 times)when the two-photon transition is resonant with the C-exciton state.Our findings uncover the SHG properties of Janus MoSSe monolayer,therefore lay the basis for its integrated frequency-doubling applications.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 20475045) the Municipal Science Foundation of Chongqing City.
文摘The interaction between congo red (CR) and amikacin (AMK) was studied by resonance Rayleigh scattering (RRS), frequency doubling scattering (FDS) and second-order scattering (SOS) combining with absorption spectrum. In a weak acidic medium, CR combined with AMK to form an ion association complex with the composition ratio of 1∶1 by electrostatic interaction, hydrophobicity and charge transferring effect. As a result, the new spectra of RRS, FDS, and SOS appeared and their intensities were enhanced greatly. The maximum wavelengths of RRS, FDS and SOS were located at 563 nm, 475 nm and 940 nm, and the scattering intensities were proportional to the concentration of AMK. These three methods have very high sensitivities, and the detection limits were 4.0 ng·mL?1 for RRS, 3.6 ng·mL?1 for FDS and 1.9 ng·mL?1 for SOS, respectively. At the same time, the methods have better selectivity. A new method for the determination of trace amounts of AMK with congo red by resonance scattering technique has been developed. The recovery for the determination of AMK in blood serum and urine sample was between 95.5% and 105.5%. In this study, the properties, such as enthalpy of formation, charge distribution and mean polarizability, were calculated by AM1 quantum chemistry method. In addition, the reaction mechanism and the reasons for the enhancement of scattering spectra were discussed.
基金supported by the National Science Foundation of China(Grant No.51079082)
文摘Based on the potential theory and perturbation techniques, the problem of second-order sloshing in a three-dimensional tank in combination with surge and sway motions is analyzed. When excitation is applied in both horizontal directions, the second-order resonance can occur when the sum frequency or the difference frequency of any two excitation components is equal to one of the natural frequencies. The resonance can also occur when the sum or difference frequency of one of the excitation frequencies and one of the natural frequencies is equal to another natural frequency.
