Monolayer transition-metal dichalcogenides（TMDs） have attracted a lot of attention for their applications in optics and optoelectronics.Molybdenum disulfide（MoS2）,as one of those important materials,has been widel...Monolayer transition-metal dichalcogenides（TMDs） have attracted a lot of attention for their applications in optics and optoelectronics.Molybdenum disulfide（MoS2）,as one of those important materials,has been widely investigated due to its direct band gap and photoluminescence（PL） in visible range.Owing to the fact that the monolayer MoS2 suffers low light absorption and emission,surface plasmon polaritons（SPPs） are used to enhance both the excitation and emission efficiencies.Here,we demonstrate that the PL of MoS2 sandwiched between 200-nm-diameter gold nanoparticle（Au NP） and 150-nm-thick gold film is improved by more than 4 times compared with bare MoS2 sample.This study shows that gap plasmons can possess more optical and optoelectronic applications incorporating with many other emerging two-dimensional materials.展开更多
Photonic structures with optical resonances beyond a single controllable mode are strongly desired for enhancing light±matter interactions and bringing about advanced photonic devices. However, the realization of...Photonic structures with optical resonances beyond a single controllable mode are strongly desired for enhancing light±matter interactions and bringing about advanced photonic devices. However, the realization of effective multimodal photonic structures has been restricted by the limited tunable range of mode manipulation, the spatial dispersions of electric fields or the polarization-dependent excitations. To overcome these limitations, we create a dualmode metasurface by integrating the plasmonic surface lattice resonance and the gap plasmonic modes;this metasurface offers a widely tunable spectral range, good overlap in the spatial distribution of electric fields, and polarization independence of excitation light. To show that such dual-mode metasurfaces are versatile platforms for enhancing light±matter interactions, we experimentally demonstrate a significant enhancement of second-harmonic generation using our design, with a conversion efficiency of 1±3 orders of magnitude larger than those previously obtained in plasmonic systems. These results may inspire new designs for functional multimodal photonic structures.展开更多
Plasmonic catalysis is emerging as a dynamic field in heterogeneous catalysis and holds great promise for the efficient utilization of solar energy.Central to the development of plasmonic catalysis is the design of ef...Plasmonic catalysis is emerging as a dynamic field in heterogeneous catalysis and holds great promise for the efficient utilization of solar energy.Central to the development of plasmonic catalysis is the design of efficient plasmonic nanocatalysts.In this report,plasmonic gap nanostructures(PGNs)on the basis of Au@poly(o-phenylenediamine)(POPD)@Pd sandwich nanostructures are synthesized as plasmonic nanocatalysts by an in-situ reduction synthetic strategy,which allows for the precise engineering of the POPD gap size between plasmonic Au and catalytic Pd components.The introduction of conducting POPD nanogap in PGNs not only effectively enhances their light harvesting capability,but also provides an effective charge transfer channel for harnessing the photogenerated hot charge carriers.In this respect,distinct gap-dependent performances in plasmon-enhanced electrocatalysis of ethanol oxidation reactions(EOR)are demonstrated with the PGN nanocatalysts and over 2.5 folds of enhancement can be achieved.A volcano plot is derived to describe the relationship between the catalytic activities and gap size of the PGN nanocatalysts,which is well explained by the interplay of their light harvesting and charge transport capabilities.These results highlight the importance of gap engineering in PGNs for plasmonic catalysis and offer the promise of developing efficient plasmonic nanocatalysts for other heterogeneous catalytic reactions.展开更多
The modulation of resonance features in microcavities is important to applications in nanophotonics.Based on the asymmetric whispering-gallery modes(WGMs)in a plasmonic resonator,we theoretically studied the mode evol...The modulation of resonance features in microcavities is important to applications in nanophotonics.Based on the asymmetric whispering-gallery modes(WGMs)in a plasmonic resonator,we theoretically studied the mode evolution in an asymmetric WGM plasmonic system.Exploiting the gap or nano-scatter in the plasmonic ring cavity,the symmetry of the system will be broken and the standing wave in the cavity will be tunable.Based on this asymmetric structure,the output coupling rate between the two cavity modes can also be tuned.Moreover,the proposed method could further be applied for sensing and detecting the position of defects in a WGM system.展开更多
Creating nanoscale and sub-nanometer gaps between noble metal nanoparticles is critical for the applications of plasmonics and nanophotonics. To realize simultaneous attainments of both the op- tical spectrum and the ...Creating nanoscale and sub-nanometer gaps between noble metal nanoparticles is critical for the applications of plasmonics and nanophotonics. To realize simultaneous attainments of both the op- tical spectrum and the gap size, the ability to tune these nanoscale gaps at the sub-nanometer scale is particularly desirable. Many nanofabrication methodologies, including electron beam lithography, self-assembly, and focused ion beams, have been tested for creating nanoscale gaps that can de- liver significant field enhancement. Here, we survey recent progress in both the reliable creation of nanoscale gaps in nanoparticle arrays using self-assemblies and in the in-situ tuning techniques at the sub-nanometer scale. Precisely tunable gaps, as we expect, will be good candidates for future investigations of surface-enhanced Raman scattering, non-linear optics, and quantum plasmonics.展开更多
Efficient excitation of surface plasmon polaritons(SPPs)remains one of the most challenging issues in areas of plasmonics related to information communication technologies.In particular,combining high SPP excitation e...Efficient excitation of surface plasmon polaritons(SPPs)remains one of the most challenging issues in areas of plasmonics related to information communication technologies.In particular,combining high SPP excitation efficiency and acceptance of any polarization of incident light appeared to be impossible to attain due to the polarized nature of SPPs.Here we demonstrate plasmonic couplers that represent arrays of gap SPP resonators producing upon reflection two orthogonal phase gradients in respective linear polarizations of incident radiation.These couplers are thereby capable of efficiently converting incident radiation with arbitrary polarization into SPPs that propagate in orthogonal directions dictated by the phase gradients.Fabricated couplers operate at telecom wavelengths and feature the coupling efficiency of,25%for either of two linear polarizations of incident radiation and directivity of SPP excitation exceeding 100.We further demonstrate that an individual wavelength-sized unit cell,representing a meta-scatterer,can also be used for efficient and polarization sensitive SPP excitation in compact plasmonics circuits.展开更多
The engineering of self-organized plasmonic metasurfaces is demonstrated using a maskless technique with defocused ion-beam sputtering and kinetically controlled deposition. The proposed reliable, cost-effective, and ...The engineering of self-organized plasmonic metasurfaces is demonstrated using a maskless technique with defocused ion-beam sputtering and kinetically controlled deposition. The proposed reliable, cost-effective, and controllable approach enables large-area （order of square centimeter） sub-wavelength periodic patterning with close-packed gold nanostrips. A multi-level variant of the method leads to high-resolution manufacturing of vertically stacked nanostrip dimer arrays, without resorting to lithographic approaches. The design of these self-organized metasurfaces is optimized by employing plasmon hybridization methods. In particular, preliminary results on the so-called gap-plasmon configuration of the nanostrip dimers, implementing magnetic dipole resonance in the near-infrared range, are reported. This resonance offers a superior sensitivity and field enhancement, compared with the more conventional electric dipole resonance. The translational invariance of the nanostrip configuration leads to a high filling factor of the hot spots. These advanced features make the large-area metasurface based on gap-plasmon nanostrip dimers very attractive for surface-enhanced linear and nonlinear spectroscopy （e.g., surface-enhanced Raman scattering） and plasmon-enhanced photon harvesting in solar and photovoltaic cells.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61590932 and 11774333)the Anhui Initiative Project in Quantum Information Technologies,China(Grant No.AHY130300)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB24030600)the National Key Research and Development Program of China(Grant No.2016YFA0301700)the Fundamental Research Funds for the Central Universities,China
文摘Monolayer transition-metal dichalcogenides（TMDs） have attracted a lot of attention for their applications in optics and optoelectronics.Molybdenum disulfide（MoS2）,as one of those important materials,has been widely investigated due to its direct band gap and photoluminescence（PL） in visible range.Owing to the fact that the monolayer MoS2 suffers low light absorption and emission,surface plasmon polaritons（SPPs） are used to enhance both the excitation and emission efficiencies.Here,we demonstrate that the PL of MoS2 sandwiched between 200-nm-diameter gold nanoparticle（Au NP） and 150-nm-thick gold film is improved by more than 4 times compared with bare MoS2 sample.This study shows that gap plasmons can possess more optical and optoelectronic applications incorporating with many other emerging two-dimensional materials.
基金supported by the National Key R&D Program of China (2016YFA0301300)the National Natural Science Foundation of China (11974437 and 91750207)+6 种基金the Key-Area Research and Development Program of Guangdong Province (2018B030329001)Guangdong Special Support Program (2017TQ04C487)Guangdong Natural Science Funds for Distinguished Young Scholars (2017B030306007)Guangdong Natural Science Funds (2020A0505140004)Pearl River S&T Nova Program of Guangzhou (201806010033)the Open Fund of IPOC (BUPT) (IPOC2019A003)the Fundamental Research Funds for the Central Universities (20lgzd30)。
文摘Photonic structures with optical resonances beyond a single controllable mode are strongly desired for enhancing light±matter interactions and bringing about advanced photonic devices. However, the realization of effective multimodal photonic structures has been restricted by the limited tunable range of mode manipulation, the spatial dispersions of electric fields or the polarization-dependent excitations. To overcome these limitations, we create a dualmode metasurface by integrating the plasmonic surface lattice resonance and the gap plasmonic modes;this metasurface offers a widely tunable spectral range, good overlap in the spatial distribution of electric fields, and polarization independence of excitation light. To show that such dual-mode metasurfaces are versatile platforms for enhancing light±matter interactions, we experimentally demonstrate a significant enhancement of second-harmonic generation using our design, with a conversion efficiency of 1±3 orders of magnitude larger than those previously obtained in plasmonic systems. These results may inspire new designs for functional multimodal photonic structures.
基金his work was supported by the National Natural Science Foundation of China(Nos.21974131,22072144,and 22102171)the Department of Science and Technology of Jilin Province(No.20200201080JC)the Natural Science Foundation of Jilin Province(No.YDZJ202201ZYTS341).
文摘Plasmonic catalysis is emerging as a dynamic field in heterogeneous catalysis and holds great promise for the efficient utilization of solar energy.Central to the development of plasmonic catalysis is the design of efficient plasmonic nanocatalysts.In this report,plasmonic gap nanostructures(PGNs)on the basis of Au@poly(o-phenylenediamine)(POPD)@Pd sandwich nanostructures are synthesized as plasmonic nanocatalysts by an in-situ reduction synthetic strategy,which allows for the precise engineering of the POPD gap size between plasmonic Au and catalytic Pd components.The introduction of conducting POPD nanogap in PGNs not only effectively enhances their light harvesting capability,but also provides an effective charge transfer channel for harnessing the photogenerated hot charge carriers.In this respect,distinct gap-dependent performances in plasmon-enhanced electrocatalysis of ethanol oxidation reactions(EOR)are demonstrated with the PGN nanocatalysts and over 2.5 folds of enhancement can be achieved.A volcano plot is derived to describe the relationship between the catalytic activities and gap size of the PGN nanocatalysts,which is well explained by the interplay of their light harvesting and charge transport capabilities.These results highlight the importance of gap engineering in PGNs for plasmonic catalysis and offer the promise of developing efficient plasmonic nanocatalysts for other heterogeneous catalytic reactions.
基金National Natural Science Foundation of China(NSFC)(61622103,61471050,61671083,11404031)Fok Ying-Tong Education Foundation for Young Teachers in the Higher Education Institutions of China(151063)Open Research Fund Program of the State Key Laboratory of Low-Dimensional Quantum Physics,Tsinghua University(KF201610)
文摘The modulation of resonance features in microcavities is important to applications in nanophotonics.Based on the asymmetric whispering-gallery modes(WGMs)in a plasmonic resonator,we theoretically studied the mode evolution in an asymmetric WGM plasmonic system.Exploiting the gap or nano-scatter in the plasmonic ring cavity,the symmetry of the system will be broken and the standing wave in the cavity will be tunable.Based on this asymmetric structure,the output coupling rate between the two cavity modes can also be tuned.Moreover,the proposed method could further be applied for sensing and detecting the position of defects in a WGM system.
文摘Creating nanoscale and sub-nanometer gaps between noble metal nanoparticles is critical for the applications of plasmonics and nanophotonics. To realize simultaneous attainments of both the op- tical spectrum and the gap size, the ability to tune these nanoscale gaps at the sub-nanometer scale is particularly desirable. Many nanofabrication methodologies, including electron beam lithography, self-assembly, and focused ion beams, have been tested for creating nanoscale gaps that can de- liver significant field enhancement. Here, we survey recent progress in both the reliable creation of nanoscale gaps in nanoparticle arrays using self-assemblies and in the in-situ tuning techniques at the sub-nanometer scale. Precisely tunable gaps, as we expect, will be good candidates for future investigations of surface-enhanced Raman scattering, non-linear optics, and quantum plasmonics.
基金The authors would like to acknowledge the financial support from the Danish Council for Independent Research(the FTP project ANAP,contract no.09-072949,and the FNU project,contract no.12-124690).
文摘Efficient excitation of surface plasmon polaritons(SPPs)remains one of the most challenging issues in areas of plasmonics related to information communication technologies.In particular,combining high SPP excitation efficiency and acceptance of any polarization of incident light appeared to be impossible to attain due to the polarized nature of SPPs.Here we demonstrate plasmonic couplers that represent arrays of gap SPP resonators producing upon reflection two orthogonal phase gradients in respective linear polarizations of incident radiation.These couplers are thereby capable of efficiently converting incident radiation with arbitrary polarization into SPPs that propagate in orthogonal directions dictated by the phase gradients.Fabricated couplers operate at telecom wavelengths and feature the coupling efficiency of,25%for either of two linear polarizations of incident radiation and directivity of SPP excitation exceeding 100.We further demonstrate that an individual wavelength-sized unit cell,representing a meta-scatterer,can also be used for efficient and polarization sensitive SPP excitation in compact plasmonics circuits.
文摘The engineering of self-organized plasmonic metasurfaces is demonstrated using a maskless technique with defocused ion-beam sputtering and kinetically controlled deposition. The proposed reliable, cost-effective, and controllable approach enables large-area （order of square centimeter） sub-wavelength periodic patterning with close-packed gold nanostrips. A multi-level variant of the method leads to high-resolution manufacturing of vertically stacked nanostrip dimer arrays, without resorting to lithographic approaches. The design of these self-organized metasurfaces is optimized by employing plasmon hybridization methods. In particular, preliminary results on the so-called gap-plasmon configuration of the nanostrip dimers, implementing magnetic dipole resonance in the near-infrared range, are reported. This resonance offers a superior sensitivity and field enhancement, compared with the more conventional electric dipole resonance. The translational invariance of the nanostrip configuration leads to a high filling factor of the hot spots. These advanced features make the large-area metasurface based on gap-plasmon nanostrip dimers very attractive for surface-enhanced linear and nonlinear spectroscopy （e.g., surface-enhanced Raman scattering） and plasmon-enhanced photon harvesting in solar and photovoltaic cells.
