Perfect Diffraction with Multiresonant Bianisotropic Metagratings

Fan, Zhiyuan; Shcherbakov, Maxim R.; Allen, Monica; Allen, Jeffery; Wenner, Brett R.; Shvets, Gennady

doi:10.1021/acsphotonics.8b00434

Cited by 63 publications

(46 citation statements)

References 63 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Metagratings (MGs), periodic structures comprised of one or a few polarizable meta-atoms per period, are attracting considerable attention lately [1][2][3][4][5][6][7] , due to their ability to manipulate beams with very high efficiencies, usually difficult to achieve with gradient metasurfaces (MS) [8,9]. Furthremore, they can also overcome realization difficulties related to conventional Huygens' and bianisotropic MSs, as the latter require microscopic design of multiple closely-packed meta-atoms per period, typically corresponding to a significantly larger number of design degrees of freedom [10][11][12][13][14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Experimental demonstration and in-depth investigation of analytically designed anomalous reflection metagratings

et al. 2019

View full text Add to dashboard Cite

We present the design, fabrication and experimental investigation of a printed circuit board (PCB) metagrating (MG) for perfect anomalous reflection. The design follows our previously developed analytical formalism, resulting in a single-element MG capable of unitary coupling of the incident wave to the specified (first order) Floquet-Bloch (FB) mode while suppressing the specular reflection. We characterize the MG performance experimentally using a bistatic scattering pattern measurement, relying on an original beam-power integration approach for accurate evaluation of the coupling to the various modes across a wide frequency range. The results show that highly-efficient wide-angle anomalous reflection is achieved, as predicted by the theory, with a relatively broadband response. In addition, the MG is found to perform well when illuminated from different angles, acting as a multichannel reflector, and to scatter efficiently also to higher-order FB modes at other frequencies, exhibiting multifunctional capabilities. Importantly, the merits of the introduced beam-integration approach, namely, its improved resilience to measurement inaccuracies or noise effects, and the implicit accommodation of different effective aperture sizes, are emphasized, highly relevant in view of the numerous recent experimental reports on anomalous reflection metasurfaces. Finally, we discuss the source for losses associated with the MG; interestingly, we show that these correlate well with edge diffraction effects, rather than (commonly assumed) power dissipation. These experimental results verify our theoretical synthesis scheme, showing that highly-efficient anomalous reflection is achievable with a realistic fabricated MG, demonstrating the practical applicability and potential mutifunctionality of analytically designed MGs for future wavefront manipulating devices.

show abstract

Section: Introductionmentioning

confidence: 99%

Experimental demonstration and in-depth investigation of analytically designed anomalous reflection metagratings

et al. 2019

View full text Add to dashboard Cite

show abstract

“…To tackle this challenge, high diffraction metagratings capable of ultrahigh angle beam bending were proposed . Breaking the symmetry of the illumination condition of the metagrating can allow high diffractions, funneling light into the desired diffraction order with high efficiencies at oblique incidences .…”

Section: Introductionmentioning

confidence: 99%

“…Alternatively, at symmetric illumination condition, asymmetric building blocks with multiple separate inclusions of different dimensions or geometries were usually considered as a necessity to generate far‐field interference for directional scattering patterns without adversely affecting each other's mode. Engineering the directional scattering patterns of periodically repeated building blocks of the metagrating demonstrates the potential to channel the incident light into desired diffraction orders at will . In particular, high‐index all‐dielectric nanoantennas featured with geometry‐tunable multiple Mie resonances for associated novel effects open a new route to selectively enhance/suppress a single diffraction order in both reflection and transmission modes.…”

Section: Introductionmentioning

confidence: 99%

“…Engineering the directional scattering patterns of periodically repeated building blocks of the metagrating demonstrates the potential to channel the incident light into desired diffraction orders at will . In particular, high‐index all‐dielectric nanoantennas featured with geometry‐tunable multiple Mie resonances for associated novel effects open a new route to selectively enhance/suppress a single diffraction order in both reflection and transmission modes. However, the innate frequency divergence of multiple separate inclusions hinders the high diffraction efficiency from wide frequency and angle range, which are highly desirable for various beam steering applications.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

All‐Dielectric Kissing‐Dimer Metagratings for Asymmetric High Diffraction

Shi

Wang

Deng

et al. 2019

Advanced Optical Materials

View full text Add to dashboard Cite

and vortex beam generators. [10][11][12] In particular, phase-gradient metasurfaces can cumulatively produce blazed phase profiles for essential far-field interference to redirect the incident wave to the anticipated direction under normal incidences. [13][14][15] However, these approaches suffer from the intrinsic restriction owing to the limited number of elements in a supercell which can fit into each periodically repeated units to discretely map the desired phase profiles. Apparently, phase-gradient metasurfaces inevitably deteriorate beam steering performance at large bending angles with significantly degraded efficiencies. [13][14][15] To tackle this challenge, high diffraction metagratings capable of ultrahigh angle beam bending were proposed. [16][17][18][19][20][21][22][23][24][25][26][27][28] Breaking the symmetry of the illumination condition of the metagrating can allow high diffractions, funneling light into the desired diffraction order with high efficiencies at oblique incidences. [16][17][18][19][20][21][22][23] Based on this scheme, high diffractions in either reflection mode using metallic metagratings [16][17][18][19] or in the transmission mode using all-dielectric metagtratings [20][21][22][23] have been achieved. Alternatively, at symmetric illumination condition, asymmetric building blocks with multiple separate inclusions of different dimensions or geometries were usually considered as a necessity to generate far-field interference for directional scattering patterns without adversely affecting each other's mode. Engineering the directional scattering patterns of periodically repeated building blocks of the metagrating demonstrates the potential to channel the incident light into desired diffraction orders at will. [24][25][26][27][28] In particular, high-index all-dielectric nanoantennas featured with geometry-tunable multiple Mie resonances for associated novel effects [26] open a new route to selectively enhance/suppress a single diffraction order in both reflection and transmission modes. However, the innate frequency divergence of multiple separate inclusions hinders the high diffraction efficiency from wide frequency and angle range, which are highly desirable for various beam steering applications. Moreover, the diffraction efficiency is strongly dependent on the separation between such asymmetric nanoantennas, which exacerbates challenges for stringent fabrication precision.Here, we propose a kind of kissing-dimer metagratings (Figure 1a), which can steer the illumination light Transcending the common perceptions of phase-gradient metasurfaces, metagratings emerge as a new paradigm for wavefront manipulation directly on the desired diffraction order with ultrahigh deflection angles. However, previous metagratings rely on directional scattering caused by multiresonant interference between multiple separate inclusions, of which the high diffraction efficiencies are only optimized with limited bandwidth and incident angle tolerance. Here, a kind of asymmetric kissing-dimer metagrating...

show abstract

“…In this work, we have considered a reflecting configuration of a 1D metagrating but the developed design approach can be generalized to deal also with transmitting and 2D metagratings. Up to date there are two methods to control transmission with metagratings: either by means of an asymmetric three-layer array [27] of electriconly "wires" or a single-layer array of bianisotropic particles [28]. In order to deal with 2D metagratings one would have to consider a 2D periodic array of point scatterers instead of a 1D array of line currents.…”

Section: Discussionmentioning

confidence: 99%

Designing Metagratings via Local Periodic Approximation: From Microwaves to Infrared

et al. 2019

View full text Add to dashboard Cite

Recently, metamaterials-inspired diffraction gratings (or metagratings) have demonstrated unprecedented efficiency in wavefront manipulation by means of relatively simple structures. Conventional one-dimensional (1D) gratings have a profile modulation in one direction and a translation symmetry in the other. In 1D metagratings, the translation invariant direction is engineered at a subwavelength scale what allows one to accurately control polarization line currents and, consequently, the scattering pattern. In bright contrast to metasurfaces, metagratings cannot be described by means of surface impedance densities (or local reflection and transmission coefficients). In this paper, we present a simulation-based design approach to construct metagratings in the "unit cell by unit cell" manner. It represents an analog of the local periodic approximation (LPA) that has been used to design space modulated metasurfaces and allows one to overcome the limitations of straightforward numerical optimization and semi-analytical procedures that have been used up to date to design metagratings. Electric and magnetic metagrating structures responding to respectively transverse electric (TE) and transverse magnetic (TM) incident plane-waves are presented to validate the proposed design approach.

show abstract

Perfect Diffraction with Multiresonant Bianisotropic Metagratings

Cited by 63 publications

References 63 publications

Experimental demonstration and in-depth investigation of analytically designed anomalous reflection metagratings

Experimental demonstration and in-depth investigation of analytically designed anomalous reflection metagratings

All‐Dielectric Kissing‐Dimer Metagratings for Asymmetric High Diffraction

Designing Metagratings via Local Periodic Approximation: From Microwaves to Infrared

Contact Info

Product

Resources

About