Spontaneous Exciton Valley Coherence in Transition Metal Dichalcogenide Monolayers Interfaced with an Anisotropic Metasurface

Jha, Pankaj; Shitrit, Nir; Ren, Xuexin; Wang, Yuan; Zhang, Xiang

doi:10.1103/physrevlett.121.116102

Cited by 50 publications

(41 citation statements)

References 46 publications

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“…On the other hand, emerging 2D materials, such as transition-metal dichalcogenide (TMDC) monolayers, are well known for their strong light-matter interactions and valley-polarized optoelectronic properties [36][37][38][39][40][41][42][43][44]. Of particular interest is the large nonlinearity of monolayer TMDCs (with chemical composition AB 2 , A = Mo, W, Ta, and Nb and B = S, Se, and Te).…”

Section: Introductionmentioning

confidence: 99%

Structuring Nonlinear Wavefront Emitted from Monolayer Transition-Metal Dichalcogenides

Hong

Zhao

et al. 2020

Research

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The growing demand for tailored nonlinearity calls for a structure with unusual phase discontinuity that allows the realization of nonlinear optical chirality, holographic imaging, and nonlinear wavefront control. Transition-metal dichalcogenide (TMDC) monolayers offer giant optical nonlinearity within a few-angstrom thickness, but limitations in optical absorption and domain size impose restriction on wavefront control of nonlinear emissions using classical light sources. In contrast, noble metal-based plasmonic nanosieves support giant field enhancements and precise nonlinear phase control, with hundred-nanometer pixel-level resolution; however, they suffer from intrinsically weak nonlinear susceptibility. Here, we report a multifunctional nonlinear interface by integrating TMDC monolayers with plasmonic nanosieves, yielding drastically different nonlinear functionalities that cannot be accessed by either constituent. Such a hybrid nonlinear interface allows second-harmonic (SH) orbital angular momentum (OAM) generation, beam steering, versatile polarization control, and holograms, with an effective SH nonlinearity χ2 of ~25 nm/V. This designer platform synergizes the TMDC monolayer and plasmonic nanosieves to empower tunable geometric phases and large field enhancement, paving the way toward multifunctional and ultracompact nonlinear optical devices.

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Section: Introductionmentioning

confidence: 99%

Structuring Nonlinear Wavefront Emitted from Monolayer Transition-Metal Dichalcogenides

Hong

Zhao

et al. 2020

Research

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“…In order to harness this valley degree of freedom, it is imperative to be able to control the coherence between excitons in the two valleys actively. Such a coherence has been demonstrated in the stimulated regime utilizing an external source, such as a laser [29] and has been theoretically proposed in the spontaneous regime, using anisotropic metasurfaces [30]. Here, we theoretically demonstrate how this spontaneous valley coherence can be achieved and manipulated by creating a heterostructure of the valley material interfaced with another anisotropic polaritonic (such as plasmonic or phononic) material.…”

mentioning

confidence: 63%

“…This effect is explained in Refs. [30,32,33] by employing a three-level V scheme comprising two levels representing the K-and K -valley excitons and one ground-state level. The quantum master equation of the interacting valley excitons in a weak-coupling regime under the rotating-wave approximation, second-order Born, and Markov approximations to the interaction Hamiltonian is given by [34][35][36]…”

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confidence: 99%

Engineering valley quantum interference in anisotropic van der Waals heterostructures

et al. 2020

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In this paper, we present a novel route to manipulate the spontaneous valley coherence in two-dimensional valleytronic materials interfaced with other layered materials hosting anisotropic polaritonic modes. We propose two implementations-one, using anisotropic plasmons in phosphorene and another with hyperbolic phonon polaritons in α-MoO 3. In particular, we show the electrostatic tunability of the spontaneous valley coherence achieving robust valley coherence values in the near-infrared wavelengths at room temperature. The tunability of this valley coherence shown in these heterostructures would enable the realization of active valleytronic quantum circuitry.

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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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Spontaneous Exciton Valley Coherence in Transition Metal Dichalcogenide Monolayers Interfaced with an Anisotropic Metasurface

Cited by 50 publications

References 46 publications

Structuring Nonlinear Wavefront Emitted from Monolayer Transition-Metal Dichalcogenides

Structuring Nonlinear Wavefront Emitted from Monolayer Transition-Metal Dichalcogenides

Engineering valley quantum interference in anisotropic van der Waals heterostructures

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

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