Role of Fano interference and incoherent pumping field on optical bistability in a four-level designed InGaN/GaN quantum dot nanostructure embedded in a unidirectional ring cavity are analyzed. It is found that intens...Role of Fano interference and incoherent pumping field on optical bistability in a four-level designed InGaN/GaN quantum dot nanostructure embedded in a unidirectional ring cavity are analyzed. It is found that intensity threshold of optical bistability can be manipulated by Fano interference. It is shown that incoherent pumping fields make the threshold of optical bistability behave differently by Fano interference. Moreover, in the presence of Fano interference the medium becomes phase-dependent. Therefore, the relative phase of applied fields can affect the behaviors of optical bistability and intensity threshold can be controlled easily.展开更多
We investigate theoretically single photon transport in one-dimensional waveguide coupled to a pair of cavities,which are denoted by the first cavity and the auxiliary cavity.Two cases with no atom and one atom embedd...We investigate theoretically single photon transport in one-dimensional waveguide coupled to a pair of cavities,which are denoted by the first cavity and the auxiliary cavity.Two cases with no atom and one atom embedded in the first cavity are discussed.The Fano dips in the transmission spectrum and locations of transparency window are calculated.When no atom is embedded in the first cavity,there exists a transparency window under the condition that the first cavity and the auxiliary cavity are not resonant.The locations of the transparency window and Fano line type depend strongly on the eigen frequency of the auxiliary cavity and the coupling strength between the auxiliary cavity and the waveguide.When one atom is embedded in the first cavity,we show that the transparency window exists even though the first cavity,the atom and the auxiliary cavity are resonant.The Fano line type is strongly dependent on the eigen frequency of the auxiliary cavity and the coupling strength.Our results have potential applications in design of quantum devices at the level of single photon,such as single photon switch and single photon routers.展开更多
Two-photon interference,a quantum phenomenon arising from the principle of indistinguishability,is a powerful tool for quantum state engineering and plays a fundamental role in various quantum technologies.These techn...Two-photon interference,a quantum phenomenon arising from the principle of indistinguishability,is a powerful tool for quantum state engineering and plays a fundamental role in various quantum technologies.These technologies demand robust and efficient sources of quantum light,as well as scalable,integrable,and multifunctional platforms.In this regard,quantum optical metasurfaces(QOMs)are emerging as promising platforms for the generation and engineering of quantum light,in particular pairs of entangled photons(biphotons)via spontaneous parametric down-conversion(SPDC).Due to the relaxation of the phase-matching condition,SPDC in QOMs allows different channels of biphoton generation,such as those supported by overlapping resonances,to occur simultaneously.In previously reported QOMs,however,SPDC was too weak to observe such effects.Here,we develop QOMs based on[110]-oriented GaAs that provide an order-of-magnitude enhancement in SPDC rate,after accounting for the spectral bandwidth,compared to any other QOMs studied to date.This boosted efficiency allows the QOMs to support the simultaneous generation of SPDC from several spectrally overlapping optical modes.Using a linear polarizer,we intentionally erase the distinguishability between the biphotons from a high-Q quasi-bound-state-in-the-continuum resonance and a low-Q Mie resonance,which results in the first-time observation of two-photon interference,shown in the form of a Fano contour,in the spectrum of biphotons.This quantum interference can enrich the generation of entangled photons in metasurfaces.Their advanced multifunctionality,improved nonlinear response,ease of fabrication,and compact footprint of[110]-GaAs QOMs position them as promising platforms to fulfill the requirements of photonic quantum technologies.展开更多
We study spectroscopic signatures of a monochromatic boson mode interacting with a T-shape double quantum dot coupled between the metallic and superconducting leads. Focusing on a weak interdot coupling, we find that ...We study spectroscopic signatures of a monochromatic boson mode interacting with a T-shape double quantum dot coupled between the metallic and superconducting leads. Focusing on a weak interdot coupling, we find that the proximity effect together with the bosonic mode are responsible for the series of Fano-type resonances appearing simultaneously at negative and positive energies. We investigate these interferometric features and discuss their influence on the subgap Andreev conductance taking into account the correlation effects driven by the Coulomb repulsion.展开更多
We fabricate arrays of metallic nanoparticle dimers with nanometer separation using electron beam lithography and angle evaporation. These ＂nanogap＂ dimers are fabricated on thin silicon nitride membranes to enable ...We fabricate arrays of metallic nanoparticle dimers with nanometer separation using electron beam lithography and angle evaporation. These ＂nanogap＂ dimers are fabricated on thin silicon nitride membranes to enable high resolution transmission electron microscope imaging of the specific nanoparticle geometries. Plasmonic resonances of the pairs are characterized by dark-field scattering micro-spectroscopy, which enables the optical scattering from individual nano- structures to be measured by using a spatially-filtered light source to illuminate a small area. Scattering spectra from individual dimers are correlated with transmis- sion electron microscope images and finite-difference time-domain simulations of their electromagnetic response, with excellent agreement between simulation and experiment. We observe a strong polarization dependence with two dominant scattering peaks in spectra taken with the polarization aligned along the dimer axis. This response arises from a unique Fano interference, in which the bright hybridized modes of an asymmetric dimer are able to couple to the dark higher- order hybridized modes through substrate-mediated coupling. The presence of this interference is strongly dependent on the nanoparticle geometry that defines the plasmon energy profile but also on the intense localization of charge at the dielectric surface in the nanogap region for separations smaller than 6 nm.展开更多
文摘Role of Fano interference and incoherent pumping field on optical bistability in a four-level designed InGaN/GaN quantum dot nanostructure embedded in a unidirectional ring cavity are analyzed. It is found that intensity threshold of optical bistability can be manipulated by Fano interference. It is shown that incoherent pumping fields make the threshold of optical bistability behave differently by Fano interference. Moreover, in the presence of Fano interference the medium becomes phase-dependent. Therefore, the relative phase of applied fields can affect the behaviors of optical bistability and intensity threshold can be controlled easily.
基金supported by the National Natural Science Foundation of China(Grant Nos.11774262 and 11975023)。
文摘We investigate theoretically single photon transport in one-dimensional waveguide coupled to a pair of cavities,which are denoted by the first cavity and the auxiliary cavity.Two cases with no atom and one atom embedded in the first cavity are discussed.The Fano dips in the transmission spectrum and locations of transparency window are calculated.When no atom is embedded in the first cavity,there exists a transparency window under the condition that the first cavity and the auxiliary cavity are not resonant.The locations of the transparency window and Fano line type depend strongly on the eigen frequency of the auxiliary cavity and the coupling strength between the auxiliary cavity and the waveguide.When one atom is embedded in the first cavity,we show that the transparency window exists even though the first cavity,the atom and the auxiliary cavity are resonant.The Fano line type is strongly dependent on the eigen frequency of the auxiliary cavity and the coupling strength.Our results have potential applications in design of quantum devices at the level of single photon,such as single photon switch and single photon routers.
基金supported by the U.S.Department of Energy(DOE)supported by BMBF,Max Planck Society and Fraunhofer Societyfunded by the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation),Project 311185701.
文摘Two-photon interference,a quantum phenomenon arising from the principle of indistinguishability,is a powerful tool for quantum state engineering and plays a fundamental role in various quantum technologies.These technologies demand robust and efficient sources of quantum light,as well as scalable,integrable,and multifunctional platforms.In this regard,quantum optical metasurfaces(QOMs)are emerging as promising platforms for the generation and engineering of quantum light,in particular pairs of entangled photons(biphotons)via spontaneous parametric down-conversion(SPDC).Due to the relaxation of the phase-matching condition,SPDC in QOMs allows different channels of biphoton generation,such as those supported by overlapping resonances,to occur simultaneously.In previously reported QOMs,however,SPDC was too weak to observe such effects.Here,we develop QOMs based on[110]-oriented GaAs that provide an order-of-magnitude enhancement in SPDC rate,after accounting for the spectral bandwidth,compared to any other QOMs studied to date.This boosted efficiency allows the QOMs to support the simultaneous generation of SPDC from several spectrally overlapping optical modes.Using a linear polarizer,we intentionally erase the distinguishability between the biphotons from a high-Q quasi-bound-state-in-the-continuum resonance and a low-Q Mie resonance,which results in the first-time observation of two-photon interference,shown in the form of a Fano contour,in the spectrum of biphotons.This quantum interference can enrich the generation of entangled photons in metasurfaces.Their advanced multifunctionality,improved nonlinear response,ease of fabrication,and compact footprint of[110]-GaAs QOMs position them as promising platforms to fulfill the requirements of photonic quantum technologies.
基金Project supported by the National Center of Science(Grant No.NN202 263138)
文摘We study spectroscopic signatures of a monochromatic boson mode interacting with a T-shape double quantum dot coupled between the metallic and superconducting leads. Focusing on a weak interdot coupling, we find that the proximity effect together with the bosonic mode are responsible for the series of Fano-type resonances appearing simultaneously at negative and positive energies. We investigate these interferometric features and discuss their influence on the subgap Andreev conductance taking into account the correlation effects driven by the Coulomb repulsion.
文摘We fabricate arrays of metallic nanoparticle dimers with nanometer separation using electron beam lithography and angle evaporation. These ＂nanogap＂ dimers are fabricated on thin silicon nitride membranes to enable high resolution transmission electron microscope imaging of the specific nanoparticle geometries. Plasmonic resonances of the pairs are characterized by dark-field scattering micro-spectroscopy, which enables the optical scattering from individual nano- structures to be measured by using a spatially-filtered light source to illuminate a small area. Scattering spectra from individual dimers are correlated with transmis- sion electron microscope images and finite-difference time-domain simulations of their electromagnetic response, with excellent agreement between simulation and experiment. We observe a strong polarization dependence with two dominant scattering peaks in spectra taken with the polarization aligned along the dimer axis. This response arises from a unique Fano interference, in which the bright hybridized modes of an asymmetric dimer are able to couple to the dark higher- order hybridized modes through substrate-mediated coupling. The presence of this interference is strongly dependent on the nanoparticle geometry that defines the plasmon energy profile but also on the intense localization of charge at the dielectric surface in the nanogap region for separations smaller than 6 nm.
