Advanced control of nonlinear beams with Pancharatnam-Berry metasurfaces

Tymchenko, Mykhailo; Gómez‐Díaz, J. S.; Lee, Jongwon; Nookala, Nishant; Belkin, Mikhail; Alù, Andrea

doi:10.1103/physrevb.94.214303

Cited by 29 publications

(36 citation statements)

References 44 publications

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“…Due to the conjugate phase of up-and down-modulated harmonics and the difference between the acquired phase of different harmonic orders, this design principle leads to several exotic phenomena such as anomalous bending, spatial decomposition of frequency harmonics and dual-polarity focusing/diffusing. In this sense, the proposed design rule has a close resemblance to the PB design rule in which a circularly-polarized light undergoing polarization conversion in a half-wave plate acquires a dispersionless geometric phase shift by rotating elements where the phase shift is conjugate for circular polarizations of opposite handness [10,11].…”

Section: Design Rule: Modulation-induced Phase Shift Of Lightmentioning

confidence: 88%

Electrically tunable harmonics in time-modulated metasurfaces for wavefront engineering

2018

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Modulation of metasurfaces in time gives rise to several exotic space-time scattering phenomena by breaking the reciprocity constraint and generation of higher-order frequency harmonics. We introduce a new design paradigm for time-modulated metasurfaces, enabling tunable engineering of the generated frequency harmonics and their emerging wavefronts by electrically controlling the phase delay in modulation. It is demonstrated that the light acquires a dispersionless phase shift regardless of incident angle and polarization, upon undergoing frequency conversion in a timemodulated metasurface which is linearly proportional to the modulation phase delay and the order of generated frequency harmonic. The conversion efficiency to the frequency harmonics is independent of modulation phase delay and only depends on the modulation depth and resonant characteristics of the metasurface, with the highest efficiency occurring in the vicinity of resonance, and decreasing away from the resonant regime. The modulation-induced phase shift allows for creating tunable spatially varying phase discontinuities with 2π span in the wavefronts of generated frequency harmonics for a wide range of frequencies and incident angles. Specifically, we apply this approach to a time-modulated metasurface in the Teraherz regime consisted of graphene-wrapped silicon microwires. For this purpose, we use an accurate and efficient semi-analytical framework based on multipole scattering. We demonstrate the utility of the design rule for tunable beam steering and focusing of generated frequency harmonics giving rise to several intriguing effects such as spatial decomposition of harmonics, anomalous bending with full coverage of angles and dual-polarity lensing. Furthermore, we investigate the angular and spectral performance of the time-modulated metasurface in manipulation of generated frequency harmonics to verify its constant phase response versus incident wavelength and angle. The nonreciprocal response of the metasurface in wavefront engineering is also studied by establishing nonreciprocal links with large isolations via modulationinduced phase shift. The proposed design approach enables a new class of high-efficiency tunable metasurfaces with wide angular and frequency bandwidth, wavefront engineering capabilities, nonreciprocal response and multi-functionality.

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Section: Design Rule: Modulation-induced Phase Shift Of Lightmentioning

confidence: 88%

Electrically tunable harmonics in time-modulated metasurfaces for wavefront engineering

2018

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“…From there, it is clear that every combination of polarizations of the impinging and outgoing beam acquires a specific phase factor that depends on the nonlinear susceptibilities and phase shifting of each element, thus allowing the full control of 0-2π phase range [99]. Such kind of nonlinear metasurfaces may provide more possibilities for controlling higher-order nonlinear holography.…”

Section: Nonlinear Holographymentioning

confidence: 99%

Metasurface holography: from fundamentals to applications

2018

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Holography has emerged as a vital approach to fully engineer the wavefronts of light since its invention dating back to the last century. However, the typically large pixel size, small field of view and limited space-bandwidth impose limitations in the on-demand high-performance applications, especially for three-dimensional displays and large-capacity data storage. Meanwhile, metasurfaces have shown great potential in controlling the propagation of light through the well-tailored scattering behavior of the constituent ultrathin planar elements with a high spatial resolution, making them suitable for holographic beam-shaping elements. Here, we review recent developments in the field of metasurface holography, from the classification of metasurfaces to the design strategies for both free-space and surface waves. By employing the concepts of holographic multiplexing, multiple information channels, such as wavelength, polarization state, spatial position and nonlinear frequency conversion, can be employed using metasurfaces. Meanwhile, the switchable metasurface holography by the integration of functional materials stimulates a gradual transition from passive to active elements. Importantly, the holography principle has become a universal and simple approach to solving inverse engineering problems for electromagnetic waves, thus allowing various related techniques to be achieved. Active holography 2D materials Phase change materialsActive metasurface holograms composed of functional graphene oxide materials [40] Active metasurface holograms integrated with GST [41] Unangemeldet

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“…where the matrices C, which contain the linear susceptibilities, are explicitly provided in Appendix C. Relations (16) are the general expressions for the second-harmonic fields scattered by a nonlinear metasurface. In these expressions, the nonlinear polarizations, P 2ω nl and M 2ω nl , play the role of nonlinear sources excited by the pump at ω.…”

Section: B Scattering Analysismentioning

confidence: 99%

“…It should be therefore possible to obtain the second-order nonlinear counterparts of the Kerker conditions [41]. However, in the very general formulation (16), it is difficult to obtain the nonlinear reflectionless conditions solely in terms of the susceptibilities because the nonlinear polarizations densities depend upon the scattering of the pump fields, as can be seen in (11) and (12). Indeed, it is, in general, particularly cumbersome to factor the linear scattering matrices out of the double dot products in (5), since (11b) (or (12b)) cannot be expressed in terms of (11a) (or (12a)).…”

Section: B Scattering Analysismentioning

confidence: 99%

“…Additionally, nonlinear metasurfaces may be used to manipulate the second-or third-harmonic scattered fields in a very elaborate fashion and with much more degrees of freedom compared to our current ability of controlling linear fields in conventional linear metasurfaces [10]- [13]. For instance, it was suggested that nonlinear metasurfaces may be used to realize functionalities such as optical switches, diodes and transistors [14], and also generate multiple holographic images based on the Pancharatnam-Berry phase effect [15], [16]. We also note the particularly interesting potential of metasurfaces to exhibit magnetic nonlinear effects [17]- [19].…”

Section: Introductionmentioning

confidence: 99%

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Homogenization and Scattering Analysis of Second-Harmonic Generation in Nonlinear Metasurfaces

Achouri¹,

Bernasconi²,

Butet³

et al. 2018

IEEE Trans. Antennas Propagat.

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We propose an extensive discussion on the homogenization and scattering analysis of second-order nonlinear metasurfaces. Our developments are based on the generalized sheet transition conditions (GSTCs) which are used to model the electromagnetic responses of nonlinear metasurfaces. The GSTCs are solved both in the frequency domain, assuming an undepleted pump regime, and in the time-domain, assuming dispersionless material properties but a possible depleted pump regime. Based on these two modeling approaches, we derive the general secondharmonic reflectionless and transmissionless conditions as well as the conditions of asymmetric reflection and transmission. We also discuss and clarify the concept of nonreciprocal scattering pertaining to nonlinear metasurfaces.

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Advanced control of nonlinear beams with Pancharatnam-Berry metasurfaces

Abstract: The application of the Pancharatnam-Berry (PB)

Cited by 29 publications

References 44 publications

Electrically tunable harmonics in time-modulated metasurfaces for wavefront engineering

Electrically tunable harmonics in time-modulated metasurfaces for wavefront engineering

Metasurface holography: from fundamentals to applications

Homogenization and Scattering Analysis of Second-Harmonic Generation in Nonlinear Metasurfaces

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