Dielectric metasurfaces play an increasingly important role in enhancing optical nonlinear generations owing to their ability to support strong light-matter interactions based on Mie-type multipolar resonances.Compare...Dielectric metasurfaces play an increasingly important role in enhancing optical nonlinear generations owing to their ability to support strong light-matter interactions based on Mie-type multipolar resonances.Compared to metasurfaces composed of the periodic arrangement of nanoparticles,inverse,so-called,membrane metasurfaces offer unique possibilities for supporting multipolar resonances,while maintaining small unit cell size,large mode volume and high field enhancement for enhancing nonlinear frequency conversion.Here,we theoretically and experimentally investigate the formation of bound states in the continuum(BICs)from silicon dimer-hole membrane metasurfaces.We demonstrate that our BIC-formed resonance features a strong and tailorable electric near-field confinement inside the silicon membrane films.Furthermore,we show that by tuning the gap between the holes,one can open a leaky channel to transform these regular BICs into quasi-BICs,which can be excited directly under normal plane wave incidence.To prove the capabilities of such metasurfaces,we demonstrate the conversion of an infrared image to the visible range,based on the Third-harmonic generation(THG)process with the resonant membrane metasurfaces.Our results suggest a new paradigm for realising efficient nonlinear photonics metadevices and hold promise for extending the applications of nonlinear structuring surfaces to new types of all-optical near-infrared imaging technologies.展开更多
Nonlinear metasurfaces have experienced rapid growth recently due to their potential in various applications,including infrared imaging and spectroscopy.However,due to the low conversion efficiencies of metasurfaces,s...Nonlinear metasurfaces have experienced rapid growth recently due to their potential in various applications,including infrared imaging and spectroscopy.However,due to the low conversion efficiencies of metasurfaces,several strategies have been adopted to enhance their performances,including employing resonances at signal or nonlinear emission wavelengths.This strategy results in a narrow operational band of the nonlinear metasurfaces,which has bottlenecked many applications,including nonlinear holography,image encoding,and nonlinear metalenses.Here,we overcome this issue by introducing a new nonlinear imaging platform utilizing a pump beam to enhance signal conversion through four-wave mixing(FWM),whereby the metasurface is resonant at the pump wavelength rather than the signal or nonlinear emissions.As a result,we demonstrate broadband nonlinear imaging for arbitrary objects using metasurfaces.A silicon disk-on-slab metasurface is introduced with an excitable guided-mode resonance at the pump wavelength.This enabled direct conversion of a broad IR image ranging from>1000 to 4000 nm into visible.Importantly,adopting FWM substantially reduces the dependence on high-power signal inputs or resonant features at the signal beam of nonlinear imaging by utilizing the quadratic relationship between the pump beam intensity and the signal conversion efficiency.Our results,therefore,unlock the potential for broadband infrared imaging capabilities with metasurfaces,making a promising advancement for next-generation all-optical infrared imaging techniques with chip-scale photonic devices.展开更多
The study of topological phases of light underpins a promising paradigm for engineering disorder-immune compact photonic devices with unusual properties.Combined with an optical gain,topological photonic structures pr...The study of topological phases of light underpins a promising paradigm for engineering disorder-immune compact photonic devices with unusual properties.Combined with an optical gain,topological photonic structures provide a novel platform for micro-and nanoscale lasers,which could benefit from nontrivial band topology and spatially localized gap states.Here,we propose and demonstrate experimentally active nanophotonic topological cavities incorporating Ⅲ-Ⅴ semiconductor quantum wells as a gain medium in the structure.We observe room-temperature lasing with a narrow spectrum,high coherence,and threshold behaviour.The emitted beam hosts a singularity encoded by a triade cavity mode that resides in the bandgap of two interfaced valley-Hall periodic photonic lattices with opposite parity breaking.Our findings make a step towards topologically controlled ultrasmall light sources with nontrivial radiation characteristics.展开更多
The flourishing of topological photonics in the last decade was achieved mainly due to developments in linear topological photonic structures.However,when nonlinearity is introduced,many intriguing questions arise.For...The flourishing of topological photonics in the last decade was achieved mainly due to developments in linear topological photonic structures.However,when nonlinearity is introduced,many intriguing questions arise.For example,are there universal fingerprints of the underlying topology when modes are coupled by nonlinearity,and what can happen to topological invariants during nonlinear propagation?To explore these questions,we experimentally demonstrate nonlinearity-induced coupling of light into topologically protected edge states using a photonic platform and develop a general theoretical framework for interpreting the mode-coupling dynamics in nonlinear topological systems.Performed on laser-written photonic Su-Schrieffer-Heeger lattices,our experiments show the nonlinear coupling of light into a nontrivial edge or interface defect channel that is otherwise not permissible due to topological protection.Our theory explains all the observations well.Furthermore,we introduce the concepts of inherited and emergent nonlinear topological phenomena as well as a protocol capable of revealing the interplay of nonlinearity and topology.These concepts are applicable to other nonlinear topological systems,both in higher dimensions and beyond our photonic platform.展开更多
基金the support from the Royal Society scholarshipsupport from the UK Research and Innovation Future Leaders Fellowship (MR/T040513/1).
文摘Dielectric metasurfaces play an increasingly important role in enhancing optical nonlinear generations owing to their ability to support strong light-matter interactions based on Mie-type multipolar resonances.Compared to metasurfaces composed of the periodic arrangement of nanoparticles,inverse,so-called,membrane metasurfaces offer unique possibilities for supporting multipolar resonances,while maintaining small unit cell size,large mode volume and high field enhancement for enhancing nonlinear frequency conversion.Here,we theoretically and experimentally investigate the formation of bound states in the continuum(BICs)from silicon dimer-hole membrane metasurfaces.We demonstrate that our BIC-formed resonance features a strong and tailorable electric near-field confinement inside the silicon membrane films.Furthermore,we show that by tuning the gap between the holes,one can open a leaky channel to transform these regular BICs into quasi-BICs,which can be excited directly under normal plane wave incidence.To prove the capabilities of such metasurfaces,we demonstrate the conversion of an infrared image to the visible range,based on the Third-harmonic generation(THG)process with the resonant membrane metasurfaces.Our results suggest a new paradigm for realising efficient nonlinear photonics metadevices and hold promise for extending the applications of nonlinear structuring surfaces to new types of all-optical near-infrared imaging technologies.
基金the Royal Society scholarshipG.S.acknowledges support from Biotechnology and Biological Council Doctoral Training Programme(BBSRC DTP)+1 种基金D.S.and D.N.N.acknowledge the support by the Australian Research Council(CE200100010 and FT230100058)L.Xu and M.Rahmani acknowledge support from the UK Research and Innovation Future Leaders Fellowship(MR/T040513/1)。
文摘Nonlinear metasurfaces have experienced rapid growth recently due to their potential in various applications,including infrared imaging and spectroscopy.However,due to the low conversion efficiencies of metasurfaces,several strategies have been adopted to enhance their performances,including employing resonances at signal or nonlinear emission wavelengths.This strategy results in a narrow operational band of the nonlinear metasurfaces,which has bottlenecked many applications,including nonlinear holography,image encoding,and nonlinear metalenses.Here,we overcome this issue by introducing a new nonlinear imaging platform utilizing a pump beam to enhance signal conversion through four-wave mixing(FWM),whereby the metasurface is resonant at the pump wavelength rather than the signal or nonlinear emissions.As a result,we demonstrate broadband nonlinear imaging for arbitrary objects using metasurfaces.A silicon disk-on-slab metasurface is introduced with an excitable guided-mode resonance at the pump wavelength.This enabled direct conversion of a broad IR image ranging from>1000 to 4000 nm into visible.Importantly,adopting FWM substantially reduces the dependence on high-power signal inputs or resonant features at the signal beam of nonlinear imaging by utilizing the quadratic relationship between the pump beam intensity and the signal conversion efficiency.Our results,therefore,unlock the potential for broadband infrared imaging capabilities with metasurfaces,making a promising advancement for next-generation all-optical infrared imaging techniques with chip-scale photonic devices.
基金supported by the Australian Research Council(grants DE190100430 and DP200101168)the National Research Foundation of Korea(NRF)funded by the Korean government(MSIT)(grant 2018R1A3A3000666).
文摘The study of topological phases of light underpins a promising paradigm for engineering disorder-immune compact photonic devices with unusual properties.Combined with an optical gain,topological photonic structures provide a novel platform for micro-and nanoscale lasers,which could benefit from nontrivial band topology and spatially localized gap states.Here,we propose and demonstrate experimentally active nanophotonic topological cavities incorporating Ⅲ-Ⅴ semiconductor quantum wells as a gain medium in the structure.We observe room-temperature lasing with a narrow spectrum,high coherence,and threshold behaviour.The emitted beam hosts a singularity encoded by a triade cavity mode that resides in the bandgap of two interfaced valley-Hall periodic photonic lattices with opposite parity breaking.Our findings make a step towards topologically controlled ultrasmall light sources with nontrivial radiation characteristics.
基金supported by the National Key R&D Program of China under Grant No.2017YFA0303800the National Natural Science Foundation(11922408,91750204,11674180),PCSIRT+5 种基金the 111 Project(No.B07013)in Chinasupport in part by the Croatian Science Foundation Grant No.IP-2016-06-5885 SynthMagIAthe QuantiXLie Center of Excellence,a project co-financed by the Croatian Government and European Union through the European Regional Development Fund-the Competitiveness and Cohesion Operational Programme(Grant KK.01.1.1.01.0004)supported by the Australian Research Council(DE19010043)supported by the Institute for Basic Science in Korea(IBS-R024-Y1)support from the Russian Foundation for Basic Research(grant No.19-52-12053).
文摘The flourishing of topological photonics in the last decade was achieved mainly due to developments in linear topological photonic structures.However,when nonlinearity is introduced,many intriguing questions arise.For example,are there universal fingerprints of the underlying topology when modes are coupled by nonlinearity,and what can happen to topological invariants during nonlinear propagation?To explore these questions,we experimentally demonstrate nonlinearity-induced coupling of light into topologically protected edge states using a photonic platform and develop a general theoretical framework for interpreting the mode-coupling dynamics in nonlinear topological systems.Performed on laser-written photonic Su-Schrieffer-Heeger lattices,our experiments show the nonlinear coupling of light into a nontrivial edge or interface defect channel that is otherwise not permissible due to topological protection.Our theory explains all the observations well.Furthermore,we introduce the concepts of inherited and emergent nonlinear topological phenomena as well as a protocol capable of revealing the interplay of nonlinearity and topology.These concepts are applicable to other nonlinear topological systems,both in higher dimensions and beyond our photonic platform.
