Optical bound states in the continuum(BICs)provide a way to engineer very narrow resonances in photonic crystals.The extended interaction time in these systems is particularly promising for the enhancement of nonlinea...Optical bound states in the continuum(BICs)provide a way to engineer very narrow resonances in photonic crystals.The extended interaction time in these systems is particularly promising for the enhancement of nonlinear optical processes and the development of the next generation of active optical devices.However,the achievable interaction strength is limited by the purely photonic character of optical BICs.Here,we mix the optical BIC in a photonic crystal slab with excitons in the atomically thin semiconductor MoSe_(2) to form nonlinear exciton-polaritons with a Rabi splitting of 27 meV,exhibiting large interaction-induced spectral blueshifts.The asymptotic BIC-like suppression of polariton radiation into the far field toward the BIC wavevector,in combination with effective reduction of the excitonic disorder through motional narrowing,results in small polariton linewidths below 3 meV.Together with a strongly wavevector-dependent Q-factor,this provides for the enhancement and control of polariton–polariton interactions and the resulting nonlinear optical effects,paving the way toward tuneable BIC-based polaritonic devices for sensing,lasing,and nonlinear optics.展开更多
Deeply subwavelength lasers(or nanolasers)are highly demanded for compact on-chip bioimaging and sensing at the nanoscale.One of the main obstacles for the development of single-particle nanolasers with all three dime...Deeply subwavelength lasers(or nanolasers)are highly demanded for compact on-chip bioimaging and sensing at the nanoscale.One of the main obstacles for the development of single-particle nanolasers with all three dimensions shorter than the emitting wavelength in the visible range is the high lasing thresholds and the resulting overheating.Here we ex-ploit exciton-polariton condensation and mirror-image Mie modes in a cuboid CsPbBr3 nanoparticle to achieve coherent emission at the visible wavelength of around 0.53μm from its ultra-small(≈0.007μm3 or≈λ3/20)semiconductor nanocav-ity.The polaritonic nature of the emission from the nanocavity localized in all three dimensions is proven by direct com-parison with corresponding one-dimensional and two-dimensional waveguiding systems with similar material parameters.Such a deeply subwavelength nanolaser is enabled not only by the high values for exciton binding energy(≈35 meV),re-fractive index(>2.5 at low temperature),and luminescence quantum yield of CsPbBr3,but also by the optimization of po-laritons condensation on the Mie resonances with quality factors improved by the metallic substrate.Moreover,the key parameters for optimal lasing conditions are intermode free spectral range and phonons spectrum in CsPbBr3,which govern polaritons condensation path.Such chemically synthesized colloidal CsPbBr3 nanolasers can be potentially de-posited on arbitrary surfaces,which makes them a versatile tool for integration with various on-chip systems.展开更多
We present and experimentally study the effects of the photonic spin–orbit coupling on the real space propagation of polariton wavepackets in planar semiconductor microcavities and polaritonic analogues of graphene.I...We present and experimentally study the effects of the photonic spin–orbit coupling on the real space propagation of polariton wavepackets in planar semiconductor microcavities and polaritonic analogues of graphene.In particular,we demonstrate the appearance of an analogue Zitterbewegung effect,a term which translates as‘trembling motion’in English,which was originally proposed for relativistic Dirac electrons and consisted of the oscillations of the centre of mass of a wavepacket in the direction perpendicular to its propagation.For a planar microcavity,we observe regular Zitterbewegung oscillations whose amplitude and period depend on the wavevector of the polaritons.We then extend these results to a honeycomb lattice of coupled microcavity resonators.Compared to the planar cavity,such lattices are inherently more tuneable and versatile,allowing simulation of the Hamiltonians of a wide range of important physical systems.We observe an oscillation pattern related to the presence of the spin-split Dirac cones in the dispersion.In both cases,the experimentally observed oscillations are in good agreement with theoretical modelling and independently measured bandstructure parameters,providing strong evidence for the observation of Zitterbewegung.展开更多
基金funding from the Ministry of Education and Science of the Russian Federation through Megagrant No.14.Y26.31.0015the UK EPSRC grant EP/P026850/1+4 种基金the project“Hybrid polaritonics”of Icelandic Science Foundationfunded by RFBR according to the research project№18-32-00527funded by RFBR,project No 19-32-90269partly funded by the Russian Science Foundation(Grant No.19-72-30003)support from the Government of the Russian Federation through the ITMO Fellowship and Professorship Program.
文摘Optical bound states in the continuum(BICs)provide a way to engineer very narrow resonances in photonic crystals.The extended interaction time in these systems is particularly promising for the enhancement of nonlinear optical processes and the development of the next generation of active optical devices.However,the achievable interaction strength is limited by the purely photonic character of optical BICs.Here,we mix the optical BIC in a photonic crystal slab with excitons in the atomically thin semiconductor MoSe_(2) to form nonlinear exciton-polaritons with a Rabi splitting of 27 meV,exhibiting large interaction-induced spectral blueshifts.The asymptotic BIC-like suppression of polariton radiation into the far field toward the BIC wavevector,in combination with effective reduction of the excitonic disorder through motional narrowing,results in small polariton linewidths below 3 meV.Together with a strongly wavevector-dependent Q-factor,this provides for the enhancement and control of polariton–polariton interactions and the resulting nonlinear optical effects,paving the way toward tuneable BIC-based polaritonic devices for sensing,lasing,and nonlinear optics.
基金supported by the Federal Program'Priority 2030'and NSFC(Project 62350610272)A.K.Samusev acknowledges Deutsche Forschungsgemeinschaft-project No.529710370。
文摘Deeply subwavelength lasers(or nanolasers)are highly demanded for compact on-chip bioimaging and sensing at the nanoscale.One of the main obstacles for the development of single-particle nanolasers with all three dimensions shorter than the emitting wavelength in the visible range is the high lasing thresholds and the resulting overheating.Here we ex-ploit exciton-polariton condensation and mirror-image Mie modes in a cuboid CsPbBr3 nanoparticle to achieve coherent emission at the visible wavelength of around 0.53μm from its ultra-small(≈0.007μm3 or≈λ3/20)semiconductor nanocav-ity.The polaritonic nature of the emission from the nanocavity localized in all three dimensions is proven by direct com-parison with corresponding one-dimensional and two-dimensional waveguiding systems with similar material parameters.Such a deeply subwavelength nanolaser is enabled not only by the high values for exciton binding energy(≈35 meV),re-fractive index(>2.5 at low temperature),and luminescence quantum yield of CsPbBr3,but also by the optimization of po-laritons condensation on the Mie resonances with quality factors improved by the metallic substrate.Moreover,the key parameters for optimal lasing conditions are intermode free spectral range and phonons spectrum in CsPbBr3,which govern polaritons condensation path.Such chemically synthesized colloidal CsPbBr3 nanolasers can be potentially de-posited on arbitrary surfaces,which makes them a versatile tool for integration with various on-chip systems.
基金This work was supported by UKRI grants EP/V026496/1 and EP/N031776/1.D.N.K.acknowledges support from STFC grant ST/W006294/1The work of A.O.,A.Y.and I.A.S.was supported by Priority2030 Federal Academic Leadership Programme.I.A.S.acknowledges support from Icelandic Research Fund(Rannis),project No.163082-051.
文摘We present and experimentally study the effects of the photonic spin–orbit coupling on the real space propagation of polariton wavepackets in planar semiconductor microcavities and polaritonic analogues of graphene.In particular,we demonstrate the appearance of an analogue Zitterbewegung effect,a term which translates as‘trembling motion’in English,which was originally proposed for relativistic Dirac electrons and consisted of the oscillations of the centre of mass of a wavepacket in the direction perpendicular to its propagation.For a planar microcavity,we observe regular Zitterbewegung oscillations whose amplitude and period depend on the wavevector of the polaritons.We then extend these results to a honeycomb lattice of coupled microcavity resonators.Compared to the planar cavity,such lattices are inherently more tuneable and versatile,allowing simulation of the Hamiltonians of a wide range of important physical systems.We observe an oscillation pattern related to the presence of the spin-split Dirac cones in the dispersion.In both cases,the experimentally observed oscillations are in good agreement with theoretical modelling and independently measured bandstructure parameters,providing strong evidence for the observation of Zitterbewegung.
