Surface plasmon polaritons(SPPs)on metal surfaces excited by p-polarized light have long been a crucial method for achieving lightmatter interactions due to their small mode-field volumes and strong optical localizati...Surface plasmon polaritons(SPPs)on metal surfaces excited by p-polarized light have long been a crucial method for achieving lightmatter interactions due to their small mode-field volumes and strong optical localization properties.However,the significant losses generated in metals greatly limit the intensity of the SPPs and their potential application scenarios.In this paper,we leverage the high refractive index properties of two-dimensional(2D)transition metal dichalcogenides(TMDCs)to generate transverse-electric(TE)polarized waves excited by s-polarized light on the surface of gold nanofilms by accurately controlling the number of the TMDC layers and the spatial refractive index variations with the structure.Unlike the SPPs excited by p-polarized light,the TE surface waves on the surface of the gold film exhibit low loss and high quality factor(Q factor).Moreover,the difference in refractive index causes the TE surface waves to be electromagnetically separated in space,lifting the electric field component in the excited TE surface waves from the surface of the metal film into the TMDCs,thereby minimizing the ohmic loss in the metal and enabling strong coupling between the TE surface waves and the two-exciton states(A-exciton and B-exciton)in the TMDCs.Experimental results demonstrated the strong coupling of TE waves with double excitons(A-exciton and B-exciton)in multilayer MoS_(2) by exciting the Au/MoS_(2) heterostructure using a KretschmannRaether configuration,showing ultrahigh Rabi splitting up to about 310 meV.Furthermore,the number of MoS_(2) layers can be accurately determined by measuring the redshift of the Rabi splitting peak of the strong coupling spectra in the Au/MoS_(2) heterostructure.Our findings open a new avenue for manipulating strong exciton-photon coupling in 2D materials and offer a novel approach for accurately characterizing the thickness of TMDCs.展开更多
Optical pulling provides a new degree of freedom in optical manipulation.It is generally believed that long-range optical pulling forces cannot be generated by the gradient of the incident field.Here,we theoretically ...Optical pulling provides a new degree of freedom in optical manipulation.It is generally believed that long-range optical pulling forces cannot be generated by the gradient of the incident field.Here,we theoretically propose and numerically demonstrate the realization of a long-range optical pulling force stemming from a self-induced gradient field in the manipulated object.In analogy to potential barriers in quantum tunnelling,we use a photonic band gap design in order to obtain the intensity gradients inside a manipulated object placed in a photonic crystal waveguide,thereby achieving a pulling force.Unlike the usual scattering-type optical pulling forces,the proposed gradient-field approach does not require precise elimination of the reflection from the manipulated objects.In particular,the Einstein-Laub formalism is applied to design this unconventional gradient force.The magnitude of the force can be enhanced by a factor of up to 50 at the optical resonance of the manipulated object in the waveguide,making it insensitive to absorption.The developed approach helps to break the limitation of scattering forces to obtain longrange optical pulling for manipulation and sorting of nanoparticles and other nano-objects.The developed principle of using the band gap to obtain a pulling force may also be applied to other types of waves,such as acoustic or water waves,which are important for numerous applications.展开更多
基金Natural Science Foundation of Guangdong Province(2025A1515012259)National Natural Science Foundation of China(12274148,12374347,12174123).
文摘Surface plasmon polaritons(SPPs)on metal surfaces excited by p-polarized light have long been a crucial method for achieving lightmatter interactions due to their small mode-field volumes and strong optical localization properties.However,the significant losses generated in metals greatly limit the intensity of the SPPs and their potential application scenarios.In this paper,we leverage the high refractive index properties of two-dimensional(2D)transition metal dichalcogenides(TMDCs)to generate transverse-electric(TE)polarized waves excited by s-polarized light on the surface of gold nanofilms by accurately controlling the number of the TMDC layers and the spatial refractive index variations with the structure.Unlike the SPPs excited by p-polarized light,the TE surface waves on the surface of the gold film exhibit low loss and high quality factor(Q factor).Moreover,the difference in refractive index causes the TE surface waves to be electromagnetically separated in space,lifting the electric field component in the excited TE surface waves from the surface of the metal film into the TMDCs,thereby minimizing the ohmic loss in the metal and enabling strong coupling between the TE surface waves and the two-exciton states(A-exciton and B-exciton)in the TMDCs.Experimental results demonstrated the strong coupling of TE waves with double excitons(A-exciton and B-exciton)in multilayer MoS_(2) by exciting the Au/MoS_(2) heterostructure using a KretschmannRaether configuration,showing ultrahigh Rabi splitting up to about 310 meV.Furthermore,the number of MoS_(2) layers can be accurately determined by measuring the redshift of the Rabi splitting peak of the strong coupling spectra in the Au/MoS_(2) heterostructure.Our findings open a new avenue for manipulating strong exciton-photon coupling in 2D materials and offer a novel approach for accurately characterizing the thickness of TMDCs.
基金Q.D.thanks for the financial support from the Natural Science Foundation of Guangdong Province,China(2019A1515011578)Department of Science and Technology of Guangdong Province,China(2020B1212060067)A.K.and A.Z.work was supported by the ERC iCOMM project(789340).
文摘Optical pulling provides a new degree of freedom in optical manipulation.It is generally believed that long-range optical pulling forces cannot be generated by the gradient of the incident field.Here,we theoretically propose and numerically demonstrate the realization of a long-range optical pulling force stemming from a self-induced gradient field in the manipulated object.In analogy to potential barriers in quantum tunnelling,we use a photonic band gap design in order to obtain the intensity gradients inside a manipulated object placed in a photonic crystal waveguide,thereby achieving a pulling force.Unlike the usual scattering-type optical pulling forces,the proposed gradient-field approach does not require precise elimination of the reflection from the manipulated objects.In particular,the Einstein-Laub formalism is applied to design this unconventional gradient force.The magnitude of the force can be enhanced by a factor of up to 50 at the optical resonance of the manipulated object in the waveguide,making it insensitive to absorption.The developed approach helps to break the limitation of scattering forces to obtain longrange optical pulling for manipulation and sorting of nanoparticles and other nano-objects.The developed principle of using the band gap to obtain a pulling force may also be applied to other types of waves,such as acoustic or water waves,which are important for numerous applications.
