Asymmetric Free-Space Light Transport at Nonlinear Metasurfaces

Shitrit, Nir; Kim, Jeongmin; Barth, David S.; Ramezani, Hamidreza; Wang, Yüan; Zhang, Xiang

doi:10.1103/physrevlett.121.046101

Cited by 30 publications

(28 citation statements)

References 29 publications

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“…Moreover, there have been few successful attempts to obtain asymmetrical transmission based on a coupled multiple-microcavity system with balanced gain and loss, i.e., parity-time symmetry [ 19 , 20 ]. Most recent scientific efforts in this field have been oriented towards exploitation of artificially-created structures, the so-called metamaterials [ 21 , 22 , 23 , 24 , 25 ]. Until now, it has been demonstrated that a complex triple-helix metamaterial structure may provide magnetic-free optical isolation within a broad spectral range [ 25 ].…”

Section: Introductionmentioning

confidence: 99%

Nonlocality-Enabled Magnetic Free Optical Isolation in Hyperbolic Metamaterials

2021

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Hereby, we present an optical isolator (optical diode) based on a hyperbolic metamaterial (HMM). We demonstrate that a grating-free planar linear non-magnetic HMM structure deposited on a high-index substrate, which, due to presence of strong spatial dispersion (non-locality), reveals asymmetrical transmittance and reflectance characteristics for light of arbitrary polarization within a wide angular and spectral range. The presented device may be efficiently utilized to completely block backward and enforce unidirectional propagation in free space and integrated systems without the use of magnetooptical or non-linear effects.

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Section: Introductionmentioning

confidence: 99%

Nonlocality-Enabled Magnetic Free Optical Isolation in Hyperbolic Metamaterials

2021

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“…Recently, it has been discovered that the metasurface can effectively manipulate the polarization state of light [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24]. For the circularly polarized (CP) incidence, a rotation-induced geometrical phase, known as the Pancharatnam-Berry (P-B) phase, is generated by rotating the anisotropic building elements [25][26][27][28][29][30][31][32][33][34][35]. Yet, this phase modulation on LCP and RCP is strongly correlated.…”

Section: Introductionmentioning

confidence: 99%

Simultaneous Generation of Arbitrary Assembly of Polarization States with Geometrical-Scaling-Induced Phase Modulation

et al. 2020

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Manipulating the polarization of light on the microscale or nanoscale is essential for integrated photonics and quantum optical devices. Nowadays, the metasurface allows one to build on-chip devices that efficiently manipulate the polarization states. However, it remains challenging to generate different types of polarization states simultaneously, which is required to encode information for quantum computing and quantum cryptography applications. By introducing geometrical-scaling-induced (GSI) phase modulations, we demonstrate that an assembly of circularly polarized (CP) and linearly polarized (LP) states can be simultaneously generated by a single metasurface made of L-shaped resonators with different geometrical features. Upon illumination, each resonator diffracts the CP state with a certain GSI phase. The interaction of these diffractions leads to the desired output beams, where the polarization state and the propagation direction can be accurately tuned by selecting the geometrical shape, size, and spatial sequence of each resonator in the unit cell. As an example of potential applications, we show that an image can be encoded with different polarization profiles at different diffraction orders and decoded with a polarization analyzer. This approach resolves a challenging problem in integrated optics and is inspiring for on-chip quantum information processing.

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“…Recent years have witnessed the emergence of "metasurfaces" based on the generalized Snell's law (GSL), [1] which provides an unprecedented way to engineering phase, amplitude, and polarization of wave and designing advanced functional devices. In electromagnetic-wave systems, [2][3][4][5][6][7][8] by introducing desirable polarization, phase, and amplitude profiles of metasurfaces, anomalous refractions or reflections have been achieved, [9,10] and complex wavefront of single or multiple subwavelength scatterers, in which the coupling effect between adjacent unit cells plays an important role in diffraction modulations. Different from conventional gratings that usually possess several diffraction orders, the metagratings can suppress undesired diffraction orders and reroute all waves towards a single propagation direction, resulting in anomalous refraction or reflection with high efficiency.…”

Section: Introductionmentioning

confidence: 99%

Aperiodic Metagratings for High‐Performance Multifunctional Acoustic Lenses

Qian

Xia

Sun

et al. 2020

Adv Materials Technologies

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modulations, including planar lenses, [11-13] holograms, [14,15] and ultrathin cloaking, [16-18] have been realized. In the acoustic systems, the metasurfaces [19-26] have also captured the fascination of researchers due to their great potential in practical applications, such as acoustic lenses, acoustic holograms, [27-31] cloaking, [32,33] vortex, and self-bending beams. [34-37] By capturing additional momenta from the metasurfaces, the incident wave can be deflected into the desired direction based on the momentum matching condition. However, the acoustic wave becomes evanescent when the total momentum of the output waves exceeds that in air. Thus, there exists a fundamental limit of critical incident angles for the wavefront modulations based on the GSL. [1] Moreover, recent researches emphasize inherent limitations of the efficiency in the design of metasurface structures, which is due to the fact that the phase-gradient metasurfaces usually neglect impedance matching constraints and thus cannot modulate all sound energy to the desired direction, with part of the incident energy scattering into unwanted parasitic diffraction. [38,39] Beyond that, the modulation efficiency gradually decreases as the angle of modulated waves deviates from the specular reflection, and thus there exists a clear trade-off between efficiency and extreme steering-angle modulation in conventional metasurfaces. To overcome the challenges above, another type of planar artificial structures has been introduced for wave modulation with high efficiency, named as metagratings. [40-44] The metagratings are usually periodic planar structures with unit cells composed Metagratings have provided great flexibility for controlling wave propagation by suppressing or enhancing diffraction of periodic unit cells or supercells with high efficiency. On the other hand, to achieve complex wavefront, modulations usually require phase profiles of the metagratings to be arbitrary. However, due to lack of a general theoretical framework, such high-efficiency aperiodic metagratings remain elusive in reality. Here, a class of aperiodic metagratings based on the extension of the Snell's law that involves both the diffraction of unit cells and the aperiodic phase modulation of metagratings in acoustics is proposed and experimentally demonstrated. The proposed aperiodic acoustic metagratings can be used to not only efficiently manipulate sound refraction or reflection for arbitrary incidence angle without the restriction of critical angles, but also to design complex wavefront modulations that enable high-performance multifunctional devices. As a proof of concept, two types of multifunctional acoustic lenses that function completely differently by adjusting the distance between two aperiodic metagratings are experimentally realized. This work provides a new pathway toward complex modulations of the wavefront and diffraction for classical waves with high efficiency.

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Asymmetric Free-Space Light Transport at Nonlinear Metasurfaces

Cited by 30 publications

References 29 publications

Nonlocality-Enabled Magnetic Free Optical Isolation in Hyperbolic Metamaterials

Nonlocality-Enabled Magnetic Free Optical Isolation in Hyperbolic Metamaterials

Simultaneous Generation of Arbitrary Assembly of Polarization States with Geometrical-Scaling-Induced Phase Modulation

Aperiodic Metagratings for High‐Performance Multifunctional Acoustic Lenses

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