As a two-dimensional planar material with low depth profile,a metasurface can generate non-classical phase distributions for the transmitted and reflected electromagnetic waves at its interface.Thus,it offers more fle...As a two-dimensional planar material with low depth profile,a metasurface can generate non-classical phase distributions for the transmitted and reflected electromagnetic waves at its interface.Thus,it offers more flexibility to control the wave front.A traditional metasurface design process mainly adopts the forward prediction algorithm,such as Finite Difference Time Domain,combined with manual parameter optimization.However,such methods are time-consuming,and it is difficult to keep the practical meta-atom spectrum being consistent with the ideal one.In addition,since the periodic boundary condition is used in the meta-atom design process,while the aperiodic condition is used in the array simulation,the coupling between neighboring meta-atoms leads to inevitable inaccuracy.In this review,representative intelligent methods for metasurface design are introduced and discussed,including machine learning,physics-information neural network,and topology optimization method.We elaborate on the principle of each approach,analyze their advantages and limitations,and discuss their potential applications.We also summarize recent advances in enabled metasurfaces for quantum optics applications.In short,this paper highlights a promising direction for intelligent metasurface designs and applications for future quantum optics research and serves as an up-to-date reference for researchers in the metasurface and metamaterial fields.展开更多
A reduction of the interprobe distance in multiprobe and double-tip scanning tunneling microscopy to the nanometer scale has been a longstanding and technically difficult challenge.Recent multiprobe systems have allow...A reduction of the interprobe distance in multiprobe and double-tip scanning tunneling microscopy to the nanometer scale has been a longstanding and technically difficult challenge.Recent multiprobe systems have allowed for significant progress by achieving distances of~30 nm using two individually driven,traditional metal wire tips.For situations where simple alignment and fixed separation can be advantageous,we present the fabrication of on-chip double-tip devices that incorporate two mechanically fixed gold tips with a tip separation of only 35nm.We utilize the excellent mechanical,insulating and dielectric properties of high-quality SiN as a base material to realize easy-to-implement,lithographically defined and mechanically stable tips.With their large contact pads and adjustable footprint,these novel tips can be easily integrated with most existing commercial combined STM/AFM systems.展开更多
The rapid development of high-QM macroscopic mechanical resonators has enabled great advances in optomechanics.Further improvements could allow for quantum-limited or quantum-enhanced applications at ambient temperatu...The rapid development of high-QM macroscopic mechanical resonators has enabled great advances in optomechanics.Further improvements could allow for quantum-limited or quantum-enhanced applications at ambient temperature.Some of the remaining challenges include the integration of high-QM structures on a chip,while simultaneously achieving large coupling strengths through an optical read-out.Here,we present a versatile fabrication method,which allows us to build fully integrated optomechanical structures.We place a photonic crystal cavity directly above a mechanical resonator with high-QM fundamental out-of-plane mode,separated by a small gap.The highly confined optical field has a large overlap with the mechanical mode,enabling strong optomechanical interaction strengths.Furthermore,we implement a novel photonic crystal design,which allows for a very large cavity photon number,a highly important feature for optomechanical experiments and sensor applications.Our versatile approach is not limited to our particular design but allows for integrating an out-of-plane optical read-out into almost any device layout.Additionally,it can be scaled to large arrays and paves the way to realizing quantum experiments and applications with mechanical resonators based on high-QM out-of-plane modes alike.展开更多
Light is a union of electric and magnetic fields,and nowhere is the complex relationship between these fields more evident than in the near fields of nanophotonic structures.There,complicated electric and magnetic fie...Light is a union of electric and magnetic fields,and nowhere is the complex relationship between these fields more evident than in the near fields of nanophotonic structures.There,complicated electric and magnetic fields varying over subwavelength scales are generally present,which results in photonic phenomena such as extraordinary optical momentum,superchiral fields,and a complex spatial evolution of optical singularities.An understanding of such phenomena requires nanoscale measurements of the complete optical field vector.Although the sensitivity of nearfield scanning optical microscopy to the complete electromagnetic field was recently demonstrated,a separation of different components required a priori knowledge of the sample.Here,we introduce a robust algorithm that can disentangle all six electric and magnetic field components from a single near-field measurement without any numerical modeling of the structure.As examples,we unravel the fields of two prototypical nanophotonic structures:a photonic crystal waveguide and a plasmonic nanowire.These results pave the way for new studies of complex photonic phenomena at the nanoscale and for the design of structures that optimize their optical behavior.展开更多
High-index nanoparticles are known to support radiationless states called anapoles,where dipolar and toroidal moments interfere to inhibit scattering to the far field.In order to exploit the striking properties arisin...High-index nanoparticles are known to support radiationless states called anapoles,where dipolar and toroidal moments interfere to inhibit scattering to the far field.In order to exploit the striking properties arising from these interference conditions in photonic integrated circuits,the particles must be driven in-plane via integrated waveguides.Here,we address the excitation of electric anapole states in silicon disks when excited on-chip at telecom wavelengths.In contrast to normal illumination,we find that the anapole condition-identified by a strong reduction of the scattering-does not overlap with the near-field energy maximum,an observation attributed to retardation effects.We experimentally verify the two distinct spectral regions in individual disks illuminated in-plane from closely placed waveguide terminations via far-field and near-field measurements.Our finding has important consequences concerning the use of anapole states and interference effects of other Mie-type resonances in high-index nanoparticles for building complex photonic integrated circuitry.展开更多
Since the performance of micro-electro-mechanical system(MEMS)-based microphones is approaching fundamental physical,design,and material limits,it has become challenging to improve them.Several works have demonstrated...Since the performance of micro-electro-mechanical system(MEMS)-based microphones is approaching fundamental physical,design,and material limits,it has become challenging to improve them.Several works have demonstrated graphene’s suitability as a microphone diaphragm.The potential for achieving smaller,more sensitive,and scalable onchip MEMS microphones is yet to be determined.To address large graphene sizes,graphene-polymer heterostructures have been proposed,but they compromise performance due to added polymer mass and stiffness.This work demonstrates the first wafer-scale integrated MEMS condenser microphones with diameters of 2R=220-320μm,thickness of 7 nm multi-layer graphene,that is suspended over a back-plate with a residual gap of 5μm.The microphones are manufactured with MEMS compatible wafer-scale technologies without any transfer steps or polymer layers that are more prone to contaminate and wrinkle the graphene.Different designs,all electrically integrated are fabricated and characterized allowing us to study the effects of the introduction of a back-plate for capacitive read-out.The devices show high mechanical compliances C_(m)=0.081-1.07μmPa^(−1)(10-100×higher than the silicon reported in the state-of-the-art diaphragms)and pull-in voltages in the range of 2-9.5 V.In addition,to validate the proof of concept,we have electrically characterized the graphene microphone when subjected to sound actuation.An estimated sensitivity of S_(1kHz)=24.3-321 mV Pa^(−1)for a V_(bias)=1.5 V was determined,which is 1.9-25.5×higher than of state-of-the-art microphone devices while having a~9×smaller area.展开更多
文摘As a two-dimensional planar material with low depth profile,a metasurface can generate non-classical phase distributions for the transmitted and reflected electromagnetic waves at its interface.Thus,it offers more flexibility to control the wave front.A traditional metasurface design process mainly adopts the forward prediction algorithm,such as Finite Difference Time Domain,combined with manual parameter optimization.However,such methods are time-consuming,and it is difficult to keep the practical meta-atom spectrum being consistent with the ideal one.In addition,since the periodic boundary condition is used in the meta-atom design process,while the aperiodic condition is used in the array simulation,the coupling between neighboring meta-atoms leads to inevitable inaccuracy.In this review,representative intelligent methods for metasurface design are introduced and discussed,including machine learning,physics-information neural network,and topology optimization method.We elaborate on the principle of each approach,analyze their advantages and limitations,and discuss their potential applications.We also summarize recent advances in enabled metasurfaces for quantum optics applications.In short,this paper highlights a promising direction for intelligent metasurface designs and applications for future quantum optics research and serves as an up-to-date reference for researchers in the metasurface and metamaterial fields.
基金This project was supported by the European Research Council(ERC StG Strong-Q and SpinMelt)and by the Netherlands Organization for Scientific Research(NWO/OCW),as part of the Frontiers of Nanoscience programas well as through Vidi grants(680–47–536,680-47-541).
文摘A reduction of the interprobe distance in multiprobe and double-tip scanning tunneling microscopy to the nanometer scale has been a longstanding and technically difficult challenge.Recent multiprobe systems have allowed for significant progress by achieving distances of~30 nm using two individually driven,traditional metal wire tips.For situations where simple alignment and fixed separation can be advantageous,we present the fabrication of on-chip double-tip devices that incorporate two mechanically fixed gold tips with a tip separation of only 35nm.We utilize the excellent mechanical,insulating and dielectric properties of high-quality SiN as a base material to realize easy-to-implement,lithographically defined and mechanically stable tips.With their large contact pads and adjustable footprint,these novel tips can be easily integrated with most existing commercial combined STM/AFM systems.
基金This work is supported by the European Research Council(ERC StG Strong-Q,676842 and ERC CoG Q-ECHOS,101001005)by the Netherlands Organization for Scientific Research(NWO/OCW)+1 种基金as part of the Frontiers of Nanoscience program,as well as through Vidi(680-47-541/994)Vrij Programma(680-92-18-04)grants.J.G.gratefully acknowledges support through a Casimir Ph.D.fellowship.
文摘The rapid development of high-QM macroscopic mechanical resonators has enabled great advances in optomechanics.Further improvements could allow for quantum-limited or quantum-enhanced applications at ambient temperature.Some of the remaining challenges include the integration of high-QM structures on a chip,while simultaneously achieving large coupling strengths through an optical read-out.Here,we present a versatile fabrication method,which allows us to build fully integrated optomechanical structures.We place a photonic crystal cavity directly above a mechanical resonator with high-QM fundamental out-of-plane mode,separated by a small gap.The highly confined optical field has a large overlap with the mechanical mode,enabling strong optomechanical interaction strengths.Furthermore,we implement a novel photonic crystal design,which allows for a very large cavity photon number,a highly important feature for optomechanical experiments and sensor applications.Our versatile approach is not limited to our particular design but allows for integrating an out-of-plane optical read-out into almost any device layout.Additionally,it can be scaled to large arrays and paves the way to realizing quantum experiments and applications with mechanical resonators based on high-QM out-of-plane modes alike.
基金the support from the European Research Council(ERC Advanced Grant 340438-CONSTANS)part of the research program Rubicon with project number 680-50-1513+1 种基金which is partly financed by the Netherlands Organization for Scientific Research(NWO)funded by the Natural Sciences and Engineering Research Council of Canada.
文摘Light is a union of electric and magnetic fields,and nowhere is the complex relationship between these fields more evident than in the near fields of nanophotonic structures.There,complicated electric and magnetic fields varying over subwavelength scales are generally present,which results in photonic phenomena such as extraordinary optical momentum,superchiral fields,and a complex spatial evolution of optical singularities.An understanding of such phenomena requires nanoscale measurements of the complete optical field vector.Although the sensitivity of nearfield scanning optical microscopy to the complete electromagnetic field was recently demonstrated,a separation of different components required a priori knowledge of the sample.Here,we introduce a robust algorithm that can disentangle all six electric and magnetic field components from a single near-field measurement without any numerical modeling of the structure.As examples,we unravel the fields of two prototypical nanophotonic structures:a photonic crystal waveguide and a plasmonic nanowire.These results pave the way for new studies of complex photonic phenomena at the nanoscale and for the design of structures that optimize their optical behavior.
基金E.D.E.acknowledges funding from Generalitat Valenciana under grant GRISOLIAP/2018/164A.I.B.acknowledges financial support by the Alexander von Humboldt Foundation.T.B.and L.K.acknowledge support from the European Research Council(ERC)Advanced Investigator Grant no.340438-CONSTANS.E.P.-C.gratefully acknowledges support from the Spanish Ministry of Science and Innovation under grant FJCI-2015-27228+1 种基金postdoctoral research stay grant CAS19/00349.A.M.thanks funding from Generalitat Valenciana(Grants No.PROMETEO/2019/123,BEST/2020/178 and IDIFEDER/2018/033)Spanish Ministry of Science,Innovation and Universities(Grants No.PRX18/00126 and PGC2018-094490-BC22).
文摘High-index nanoparticles are known to support radiationless states called anapoles,where dipolar and toroidal moments interfere to inhibit scattering to the far field.In order to exploit the striking properties arising from these interference conditions in photonic integrated circuits,the particles must be driven in-plane via integrated waveguides.Here,we address the excitation of electric anapole states in silicon disks when excited on-chip at telecom wavelengths.In contrast to normal illumination,we find that the anapole condition-identified by a strong reduction of the scattering-does not overlap with the near-field energy maximum,an observation attributed to retardation effects.We experimentally verify the two distinct spectral regions in individual disks illuminated in-plane from closely placed waveguide terminations via far-field and near-field measurements.Our finding has important consequences concerning the use of anapole states and interference effects of other Mie-type resonances in high-index nanoparticles for building complex photonic integrated circuitry.
基金funding from European Union’s Horizon 2020 research and innovation program under Grant Agreement No.881603(Graphene Flagship).
文摘Since the performance of micro-electro-mechanical system(MEMS)-based microphones is approaching fundamental physical,design,and material limits,it has become challenging to improve them.Several works have demonstrated graphene’s suitability as a microphone diaphragm.The potential for achieving smaller,more sensitive,and scalable onchip MEMS microphones is yet to be determined.To address large graphene sizes,graphene-polymer heterostructures have been proposed,but they compromise performance due to added polymer mass and stiffness.This work demonstrates the first wafer-scale integrated MEMS condenser microphones with diameters of 2R=220-320μm,thickness of 7 nm multi-layer graphene,that is suspended over a back-plate with a residual gap of 5μm.The microphones are manufactured with MEMS compatible wafer-scale technologies without any transfer steps or polymer layers that are more prone to contaminate and wrinkle the graphene.Different designs,all electrically integrated are fabricated and characterized allowing us to study the effects of the introduction of a back-plate for capacitive read-out.The devices show high mechanical compliances C_(m)=0.081-1.07μmPa^(−1)(10-100×higher than the silicon reported in the state-of-the-art diaphragms)and pull-in voltages in the range of 2-9.5 V.In addition,to validate the proof of concept,we have electrically characterized the graphene microphone when subjected to sound actuation.An estimated sensitivity of S_(1kHz)=24.3-321 mV Pa^(−1)for a V_(bias)=1.5 V was determined,which is 1.9-25.5×higher than of state-of-the-art microphone devices while having a~9×smaller area.
