Scattering of waves, e.g., light, due to medium inhomogeneity is ubiquitous in physics and isconsidered detrimental for many applications. Wavefront shaping technology is a powerful tool to defeatscattering and focus ...Scattering of waves, e.g., light, due to medium inhomogeneity is ubiquitous in physics and isconsidered detrimental for many applications. Wavefront shaping technology is a powerful tool to defeatscattering and focus light through inhomogeneous media, which is vital for optical imaging, communication,therapy, etc. Wavefront shaping based on the scattering matrix (SM) is extremely useful in handling dynamicprocesses in the linear regime. However, the implementation of such a method for controlling light in nonlinearmedia is still a challenge and has been unexplored until now. We report a method to determine the SM ofnonlinear scattering media with second-order nonlinearity. We experimentally demonstrate its feasibility inwavefront control and realize focusing of nonlinear signals through strongly scattering quadratic media.Moreover, we show that statistical properties of this SM still follow the random matrix theory. The scattering-matrix approach of nonlinear scattering medium opens a path toward nonlinear signal recovery, nonlinearimaging, microscopic object tracking, and complex environment quantum information processing.展开更多
Lens is a basic optical element that is widely used in daily life,such as in cameras,glasses,and microscopes.Conventional lenses are designed based on the classical refractive optics,which results in inevitable imagin...Lens is a basic optical element that is widely used in daily life,such as in cameras,glasses,and microscopes.Conventional lenses are designed based on the classical refractive optics,which results in inevitable imaging aberrations,such as chromatic aberration,spherical aberration and coma.To solve these problems,conventional imaging systems impose multiple curved lenses with different thicknesses and materials to eliminate these aberrations.As a unique photonic technology,metasurfaces can accurately manipulate the wavefront of light to produce fascinating and peculiar optical phenomena,which has stimulated researchers9 extensive interests in the field of planar optics.Starting from the introduction of phase modulation methods,this review summarizes the design principles and characteristics of metalenses.Although the imaging quality of existing metalenses is not necessarily better than that of conventional lenses,the multi-dimensional and multi-degree-of-freedom control of metasurfaces provides metalenses with novel functions that are extremely challenging or impossible to achieve with conventional lenses.展开更多
Controlling the phase of an electromagnetic field using plasmonic nanostructures provides a versatile way to manipulate light at the nanoscale.Broadband phase modulation has been demonstrated using inhomogeneous metas...Controlling the phase of an electromagnetic field using plasmonic nanostructures provides a versatile way to manipulate light at the nanoscale.Broadband phase modulation has been demonstrated using inhomogeneous metasurfaces with different geometries;however,for many applications such as filtering,hyperspectral imaging and color holography,narrowband frequency selectivity is a key functionality.In this work,we demonstrate,both theoretically and experimentally,a narrowband metasurface that relies on Fano resonances to control the propagation of light.By geometrically tuning the sub-radiant modes with respect to a fixed super-radiant resonance,we can create a phase modulation along the surface within a narrow spectral range.The resulting anomalous reflection measured for such a Fano-resonant metasurface exhibits a 100 nm bandwidth and a color routing efficiency of up to 81%at a central wavelength ofλ=750 nm.The design flexibility provided by this Fano-assisted metasurface for colorselective light manipulation is further illustrated by demonstrating a highly directional color-routing effect between two channels,atλ=532 and 660 nm,without any crosstalk.展开更多
Metasurfaces offer unprecedented flexibility in the design and control of light propagation,replacing bulk optical components and exhibiting exotic optical effects.One of the basic properties of the metasurfaces,which...Metasurfaces offer unprecedented flexibility in the design and control of light propagation,replacing bulk optical components and exhibiting exotic optical effects.One of the basic properties of the metasurfaces,which renders them as frequency selective surfaces,is the ability to transmit or reflect radiation within a narrow frequency band that can be engineered on demand.Here we introduce and demonstrate experimentally in the THz domain the concept of wavevector selective surfaces–metasurfaces transparent only within a narrow range of light propagation directions operating effectively as tunnel vision filters.Practical implementations of the new concept include applications in wavefront manipulation,observational instruments,vision and free-space communication in light-scattering environments.展开更多
In the past decade, one-way manipulation of sound has attracted rapidly growing attention with application potentials in a plethora of scenarios ranging from ultrasound imaging to noise control. Here we propose a desi...In the past decade, one-way manipulation of sound has attracted rapidly growing attention with application potentials in a plethora of scenarios ranging from ultrasound imaging to noise control. Here we propose a design of a planar device capable of unidirectionally harnessing the transmitted wavefront for broadband airborne sound. Our mechanism is to use the broken spatial symmetry to give rise to different critical angles for plane waves incident along opposite directions.Along the positive direction, the incoming sound is allowed to pass with high efficiency and be arbitrarily molded into the desired shape while any reversed wave undergoes a total reflection. We analytically derive the working bandwidth and incident angle range, and present a practical implementation of our strategy. The performance of our proposed device is demonstrated both theoretically and numerically via distinct examples of production of broadband anomalous refraction,acoustic focusing and non-diffractive beams for forward transmitted wave while virtually blocking the reversed waves.Bearing advantages of simple design, planar profile, broad bandwidth and high efficiency, our design opens the possibility for novel one-way acoustic device and may have important impact on diverse applications in need of special control of airborne sound.展开更多
We report on the first demonstration of a proof-of-principle optical fiber‘meta-tip’,which integrates a phase-gradient plasmonic metasurface on the fiber tip.For illustration and validation purposes,we present numer...We report on the first demonstration of a proof-of-principle optical fiber‘meta-tip’,which integrates a phase-gradient plasmonic metasurface on the fiber tip.For illustration and validation purposes,we present numerical and experimental results pertaining to various prototypes implementing generalized forms of the Snell’s transmission/reflection laws at near-infrared wavelengths.In particular,we demonstrate several examples of beam steering and coupling with surface waves,in fairly good agreement with theory.Our results constitute a first step toward the integration of unprecedented(metasurface-enabled)light-manipulation capabilities in optical-fiber technology.By further enriching the emergent‘lab-on-fiber’framework,this may pave the way for the widespread diffusion of optical metasurfaces in real-world applications to communications,signal processing,imaging and sensing.展开更多
基金supported in part by the National Key R&D Program of China (No. 2018YFA0306301)the National Natural Science Foundation of China (Nos. 12192252, 62022058, 12074252, and 12004245)+2 种基金the Shanghai Municipal Science and Technology Major Project (No. 2019SHZDZX01ZX06)the Shanghai Rising-Star Program (No. 20QA1405400)the Yangyang Development Fund.
文摘Scattering of waves, e.g., light, due to medium inhomogeneity is ubiquitous in physics and isconsidered detrimental for many applications. Wavefront shaping technology is a powerful tool to defeatscattering and focus light through inhomogeneous media, which is vital for optical imaging, communication,therapy, etc. Wavefront shaping based on the scattering matrix (SM) is extremely useful in handling dynamicprocesses in the linear regime. However, the implementation of such a method for controlling light in nonlinearmedia is still a challenge and has been unexplored until now. We report a method to determine the SM ofnonlinear scattering media with second-order nonlinearity. We experimentally demonstrate its feasibility inwavefront control and realize focusing of nonlinear signals through strongly scattering quadratic media.Moreover, we show that statistical properties of this SM still follow the random matrix theory. The scattering-matrix approach of nonlinear scattering medium opens a path toward nonlinear signal recovery, nonlinearimaging, microscopic object tracking, and complex environment quantum information processing.
基金the National Key R&D Program of China(No.2020YFC2007102)the National Natural Science Foundation of China(Grant No.12074444)+1 种基金Guangdong Basic and Applied Basic Research Foundation(No.2020A1515011184)Innovation Group Project of Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai).
文摘Lens is a basic optical element that is widely used in daily life,such as in cameras,glasses,and microscopes.Conventional lenses are designed based on the classical refractive optics,which results in inevitable imaging aberrations,such as chromatic aberration,spherical aberration and coma.To solve these problems,conventional imaging systems impose multiple curved lenses with different thicknesses and materials to eliminate these aberrations.As a unique photonic technology,metasurfaces can accurately manipulate the wavefront of light to produce fascinating and peculiar optical phenomena,which has stimulated researchers9 extensive interests in the field of planar optics.Starting from the introduction of phase modulation methods,this review summarizes the design principles and characteristics of metalenses.Although the imaging quality of existing metalenses is not necessarily better than that of conventional lenses,the multi-dimensional and multi-degree-of-freedom control of metasurfaces provides metalenses with novel functions that are extremely challenging or impossible to achieve with conventional lenses.
基金supported by the Swiss National Science Foundation(grants 200020_153662 and 200021_162453).
文摘Controlling the phase of an electromagnetic field using plasmonic nanostructures provides a versatile way to manipulate light at the nanoscale.Broadband phase modulation has been demonstrated using inhomogeneous metasurfaces with different geometries;however,for many applications such as filtering,hyperspectral imaging and color holography,narrowband frequency selectivity is a key functionality.In this work,we demonstrate,both theoretically and experimentally,a narrowband metasurface that relies on Fano resonances to control the propagation of light.By geometrically tuning the sub-radiant modes with respect to a fixed super-radiant resonance,we can create a phase modulation along the surface within a narrow spectral range.The resulting anomalous reflection measured for such a Fano-resonant metasurface exhibits a 100 nm bandwidth and a color routing efficiency of up to 81%at a central wavelength ofλ=750 nm.The design flexibility provided by this Fano-assisted metasurface for colorselective light manipulation is further illustrated by demonstrating a highly directional color-routing effect between two channels,atλ=532 and 660 nm,without any crosstalk.
基金This work is supported by the UK’s Engineering and Physical Sciences Research Council through Career Acceleration Fellowship EP/G00515X/1(V.A.F.)Programme grant EP/G060363/1,by the Royal Society,and by the MOE Singapore grant MOE2011-T3-1-005
文摘Metasurfaces offer unprecedented flexibility in the design and control of light propagation,replacing bulk optical components and exhibiting exotic optical effects.One of the basic properties of the metasurfaces,which renders them as frequency selective surfaces,is the ability to transmit or reflect radiation within a narrow frequency band that can be engineered on demand.Here we introduce and demonstrate experimentally in the THz domain the concept of wavevector selective surfaces–metasurfaces transparent only within a narrow range of light propagation directions operating effectively as tunnel vision filters.Practical implementations of the new concept include applications in wavefront manipulation,observational instruments,vision and free-space communication in light-scattering environments.
基金Project supported by National Key R&D Program of China (Grant No. 2017YFA0303700)the National Natural Science Foundation of China (Grant Nos. 11634006, 11374157, and 81127901)+1 种基金a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Innovation Special Zone of National Defense Science and Technology and High-Performance Computing Center of Collaborative Innovation Center of Advanced Microstructures。
文摘In the past decade, one-way manipulation of sound has attracted rapidly growing attention with application potentials in a plethora of scenarios ranging from ultrasound imaging to noise control. Here we propose a design of a planar device capable of unidirectionally harnessing the transmitted wavefront for broadband airborne sound. Our mechanism is to use the broken spatial symmetry to give rise to different critical angles for plane waves incident along opposite directions.Along the positive direction, the incoming sound is allowed to pass with high efficiency and be arbitrarily molded into the desired shape while any reversed wave undergoes a total reflection. We analytically derive the working bandwidth and incident angle range, and present a practical implementation of our strategy. The performance of our proposed device is demonstrated both theoretically and numerically via distinct examples of production of broadband anomalous refraction,acoustic focusing and non-diffractive beams for forward transmitted wave while virtually blocking the reversed waves.Bearing advantages of simple design, planar profile, broad bandwidth and high efficiency, our design opens the possibility for novel one-way acoustic device and may have important impact on diverse applications in need of special control of airborne sound.
文摘We report on the first demonstration of a proof-of-principle optical fiber‘meta-tip’,which integrates a phase-gradient plasmonic metasurface on the fiber tip.For illustration and validation purposes,we present numerical and experimental results pertaining to various prototypes implementing generalized forms of the Snell’s transmission/reflection laws at near-infrared wavelengths.In particular,we demonstrate several examples of beam steering and coupling with surface waves,in fairly good agreement with theory.Our results constitute a first step toward the integration of unprecedented(metasurface-enabled)light-manipulation capabilities in optical-fiber technology.By further enriching the emergent‘lab-on-fiber’framework,this may pave the way for the widespread diffusion of optical metasurfaces in real-world applications to communications,signal processing,imaging and sensing.
