Optical metasurfaces,i.e.arrays of nanoantennas with sub-wavelength size and separation,enable the manipulation of light-matter interactions in miniaturized optical components with no classical counterparts.Six decade...Optical metasurfaces,i.e.arrays of nanoantennas with sub-wavelength size and separation,enable the manipulation of light-matter interactions in miniaturized optical components with no classical counterparts.Six decades after the first ob-servation of the second harmonic generation(SHG)in bulk crystals,these devices are expected to break new ground in the field of nonlinear optics,shifting the focus from the phase matching approach achieved within long propagation dis-tances to that of near-field resonances interplay in leaky nanocavities.Here we review the recent progress in SHG with all-dielectric metasurfaces.We discuss the most used technological platforms which underpinned such advances and analyze different SHG control approaches.We finally compare their performances with other well-established technolo-gies,with the hope to delineate the current state-of-the-art and figure out a few scenarios in which these devices might soon offer unprecedented opportunities.展开更多
Nonlinear frequency conversion is one of the most fundamental processes in nonlinear optics.It has a wide range of applications in our daily lives,including novel light sources,sensing,and information processing.It is...Nonlinear frequency conversion is one of the most fundamental processes in nonlinear optics.It has a wide range of applications in our daily lives,including novel light sources,sensing,and information processing.It is usually assumed that nonlinear frequency conversion requires large crystals that gradually accumulate a strong effect.However,the large size of nonlinear crystals is not compatible with the miniaturisation of modern photonic and optoelectronic systems.Therefore,shrinking the nonlinear structures down to the nanoscale,while keeping favourable conversion efficiencies,is of great importance for future photonics applications.In the last decade,researchers have studied the strategies for enhancing the nonlinear efficiencies at the nanoscale,e.g.by employing different nonlinear materials,resonant couplings and hybridization techniques.In this paper,we provide a compact review of the nanomaterials-based efforts,ranging from metal to dielectric and semiconductor nanostructures,including their relevant nanofabrication techniques.展开更多
Vortex beams are currently drawing a great deal of interest,from fundamental research to several promising applications.While their generation in bulky optical devices limits their use in integrated complex systems,me...Vortex beams are currently drawing a great deal of interest,from fundamental research to several promising applications.While their generation in bulky optical devices limits their use in integrated complex systems,metasurfaces have recently proven successful in creating optical vortices,especially in the linear regime.In the nonlinear domain,of strategic importance for the future of classical and quantum information,to date orbital angular momentum has only been created in qualitative ways,without discussing discrepancies between design and experimental results.Here,we demonstrate and analyze the generation of high-purity second harmonic(SH)optical vortices via dielectric meta-holograms.Through full-wave simulations and a proper fabrication protocol,we achieve efficient frequency doubling of an unstructured pump beam into SH vortices with topological charges from 1 to 10.Interferometric and modal-purity measurements confrm the generation of high-quality SH vortices with minimal deviations from the intended design thanks to a quasi-local control over the SH phase.Through systematic comparisons between experimental data and semi-analytical calculations,we also provide a clear insight into the occurrence of ghost vortices in the metasurface-generated harmonic beams,highlighting the importance of simple designs that can be readily transposed into fabricated devices with high fidelity.Our findings underscore the potential of nonlinear dielectric metasurfaces for versatile structured-light generation and manipulation,paving the way for future developments in integrated photonic systems.展开更多
Switching of light polarization on the sub-picosecond timescale is a crucial functionality for applications in a variety of contexts,including telecommunications,biology and chemistry.The ability to control polarizati...Switching of light polarization on the sub-picosecond timescale is a crucial functionality for applications in a variety of contexts,including telecommunications,biology and chemistry.The ability to control polarization at ultrafast speed would pave the way for the development of unprecedented free-space optical links and of novel techniques for probing dynamical processes in complex systems,as chiral molecules.Such high switching speeds can only be reached with an all-optical paradigm,i.e.,engineering active platforms capable of controlling light polarization via ultrashort laser pulses.Here we demonstrate giant modulation of dichroism and birefringence in an all-dielectric metasurface,achieved at low fluences of the optical control beam.This performance,which leverages the many degrees of freedom offered by all-dielectric active metasurfaces,is obtained by combining a high-quality factor nonlocal resonance with the giant third-order optical nonlinearity dictated by photogenerated hot carriers at the semiconductor band edge.展开更多
Infrared imaging is a crucial technique in a multitude of applications,including night vision,autonomous vehicle navigation,optical tomography,and food quality control.Conventional infrared imaging technologies,howeve...Infrared imaging is a crucial technique in a multitude of applications,including night vision,autonomous vehicle navigation,optical tomography,and food quality control.Conventional infrared imaging technologies,however,require the use of materials such as narrow bandgap semiconductors,which are sensitive to thermal noise and often require cryogenic cooling.We demonstrate a compact all-optical alternative to perform infrared imaging in a metasurface composed of GaAs semiconductor nanoantennas,using a nonlinear wave-mixing process.We experimentally show the upconversion of short-wave infrared wavelengths via the coherent parametric process of sum-frequency generation.In this process,an infrared image of a target is mixed inside the metasurface with a strong pump beam,translating the image from the infrared to the visible in a nanoscale ultrathin imaging device.Our results open up new opportunities for the development of compact infrared imaging devices with applications in infrared vision and life sciences.展开更多
Dielectric nanocavities are emerging as a versatile and powerful tool for the linear and nonlinear manipulation of light at the nanoscale. In this work, we exploit the effective coupling of electric and toroidal modes...Dielectric nanocavities are emerging as a versatile and powerful tool for the linear and nonlinear manipulation of light at the nanoscale. In this work, we exploit the effective coupling of electric and toroidal modes in AIGaAs nanodimers to locally enhance both electric and magnetic fields while minimizing the optical scattering, thereby optimizing their second-harmonic generation efficiency with respect to the case of a single isolated nanodisk. We also demonstrate that proper near-field coupling can provide fitrther degrees of freedom to control the polari- zation state and the radiation diagram of the second-harmonic field.展开更多
基金financial support by ANR through the NANOPAIR project.
文摘Optical metasurfaces,i.e.arrays of nanoantennas with sub-wavelength size and separation,enable the manipulation of light-matter interactions in miniaturized optical components with no classical counterparts.Six decades after the first ob-servation of the second harmonic generation(SHG)in bulk crystals,these devices are expected to break new ground in the field of nonlinear optics,shifting the focus from the phase matching approach achieved within long propagation dis-tances to that of near-field resonances interplay in leaky nanocavities.Here we review the recent progress in SHG with all-dielectric metasurfaces.We discuss the most used technological platforms which underpinned such advances and analyze different SHG control approaches.We finally compare their performances with other well-established technolo-gies,with the hope to delineate the current state-of-the-art and figure out a few scenarios in which these devices might soon offer unprecedented opportunities.
文摘Nonlinear frequency conversion is one of the most fundamental processes in nonlinear optics.It has a wide range of applications in our daily lives,including novel light sources,sensing,and information processing.It is usually assumed that nonlinear frequency conversion requires large crystals that gradually accumulate a strong effect.However,the large size of nonlinear crystals is not compatible with the miniaturisation of modern photonic and optoelectronic systems.Therefore,shrinking the nonlinear structures down to the nanoscale,while keeping favourable conversion efficiencies,is of great importance for future photonics applications.In the last decade,researchers have studied the strategies for enhancing the nonlinear efficiencies at the nanoscale,e.g.by employing different nonlinear materials,resonant couplings and hybridization techniques.In this paper,we provide a compact review of the nanomaterials-based efforts,ranging from metal to dielectric and semiconductor nanostructures,including their relevant nanofabrication techniques.
基金the METAFAST H2020-FETOPEN-2018-2020 project(grant agreement no.899673)the MEGAPHONE project(ANR-22-CE92-0090)from Agence Nationale de la Recherche+2 种基金support the METAFAST H2020-FETOPEN-2018-2020 project(grant agreement no.899673)the MEGAPHONE project(ANR-22-CE92-0090)from Agence Nationale de la Recherchesupport from the European Research Council grant FORWARD(reference:771688).
文摘Vortex beams are currently drawing a great deal of interest,from fundamental research to several promising applications.While their generation in bulky optical devices limits their use in integrated complex systems,metasurfaces have recently proven successful in creating optical vortices,especially in the linear regime.In the nonlinear domain,of strategic importance for the future of classical and quantum information,to date orbital angular momentum has only been created in qualitative ways,without discussing discrepancies between design and experimental results.Here,we demonstrate and analyze the generation of high-purity second harmonic(SH)optical vortices via dielectric meta-holograms.Through full-wave simulations and a proper fabrication protocol,we achieve efficient frequency doubling of an unstructured pump beam into SH vortices with topological charges from 1 to 10.Interferometric and modal-purity measurements confrm the generation of high-quality SH vortices with minimal deviations from the intended design thanks to a quasi-local control over the SH phase.Through systematic comparisons between experimental data and semi-analytical calculations,we also provide a clear insight into the occurrence of ghost vortices in the metasurface-generated harmonic beams,highlighting the importance of simple designs that can be readily transposed into fabricated devices with high fidelity.Our findings underscore the potential of nonlinear dielectric metasurfaces for versatile structured-light generation and manipulation,paving the way for future developments in integrated photonic systems.
基金funding from the European Union Horizon 2020 Research and Innovation program under grant agreement no.899673This work reflects only authors’view and the European Commission is not responsible for any use that may be made of the information it contains.G.D.V.acknowledges the support from the HOTMETA project under the PRIN 2022 MUR program funded by the European Union—Next Generation EU—“PNRR-M4C2,investimento 1.1—“Fondo PRIN 2022”—HOT-carrier METasurfaces for Advanced photonics(HOTMETA)+1 种基金contract no.2022LENW33—CUP:D53D23002290006”.A.S.,G.C.,M.M.and G.D.V.acknowledge financial support by the European Union’s NextGenerationEU Programme with the I-PHOQS Infrastructure[IR0000016,ID D2B8D520,CUP B53C22001750006]“Integrated infrastructure initiative in Photonic and Quantum Sciences”.The work is partly supported by the French RENATECH networksupport by the European Union-NextGenerationEU,through the National Recovery and Resilience Plan of the Republic of Bulgaria,SUMMIT BG-RRP-2.004-0008-C0.DN acknowledges the support of the Australian Research Council(CE200100010).
文摘Switching of light polarization on the sub-picosecond timescale is a crucial functionality for applications in a variety of contexts,including telecommunications,biology and chemistry.The ability to control polarization at ultrafast speed would pave the way for the development of unprecedented free-space optical links and of novel techniques for probing dynamical processes in complex systems,as chiral molecules.Such high switching speeds can only be reached with an all-optical paradigm,i.e.,engineering active platforms capable of controlling light polarization via ultrashort laser pulses.Here we demonstrate giant modulation of dichroism and birefringence in an all-dielectric metasurface,achieved at low fluences of the optical control beam.This performance,which leverages the many degrees of freedom offered by all-dielectric active metasurfaces,is obtained by combining a high-quality factor nonlocal resonance with the giant third-order optical nonlinearity dictated by photogenerated hot carriers at the semiconductor band edge.
基金The authors acknowledge the use of the Australian National Fabrication Facility(ANFF),ACT Node.Rocio CamachoMorales acknowledges a grant from the Consejo Nacional de Ciencia y Tecnología(CONACYT),MexicoNikolay Dimitrov and Lyubomir Stoyanov acknowledge a grant from the EU Marie-Curie RISE program NOCTURNO+1 种基金Mohsen Rahmani acknowledges support from the UK Research and Innovation Future Leaders Fellowship(MR/T040513/1)Dragomir N.Neshev acknowledges a grant from the Australian Research Council(CE20010001,DP190101559).
文摘Infrared imaging is a crucial technique in a multitude of applications,including night vision,autonomous vehicle navigation,optical tomography,and food quality control.Conventional infrared imaging technologies,however,require the use of materials such as narrow bandgap semiconductors,which are sensitive to thermal noise and often require cryogenic cooling.We demonstrate a compact all-optical alternative to perform infrared imaging in a metasurface composed of GaAs semiconductor nanoantennas,using a nonlinear wave-mixing process.We experimentally show the upconversion of short-wave infrared wavelengths via the coherent parametric process of sum-frequency generation.In this process,an infrared image of a target is mixed inside the metasurface with a strong pump beam,translating the image from the infrared to the visible in a nanoscale ultrathin imaging device.Our results open up new opportunities for the development of compact infrared imaging devices with applications in infrared vision and life sciences.
基金Australian Research Council(ARC)Education,Audiovisual and Culture Executive Agency(EACEA)(5659/002-001)SATT IdF-Innov UniversitéSorbonne(Double Culture-PhD program)
文摘Dielectric nanocavities are emerging as a versatile and powerful tool for the linear and nonlinear manipulation of light at the nanoscale. In this work, we exploit the effective coupling of electric and toroidal modes in AIGaAs nanodimers to locally enhance both electric and magnetic fields while minimizing the optical scattering, thereby optimizing their second-harmonic generation efficiency with respect to the case of a single isolated nanodisk. We also demonstrate that proper near-field coupling can provide fitrther degrees of freedom to control the polari- zation state and the radiation diagram of the second-harmonic field.
