In-plane anisotropic third-harmonic generation from germanium arsenide thin flakes

2021

Sci Rep

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Vertically stacked van der Waals (vdW) heterostructures have introduced a unique way to engineer optical and electronic responses in multifunctional photonic and quantum devices. However, the technical challenges associated with the artificially fabricated vertical heterostructures have emerged as a bottleneck to restrict their proficient utilization, which emphasizes the necessity of exploring naturally occurring vdW heterostructures. As one type of naturally occurring vdW heterostructures, franckeite has recently attracted significant interest in optoelectronic applications, but the understanding of light–matter interactions in such layered mineral is still very limited especially in the nonlinear optical regime. Herein, the anisotropic Raman scattering and third-harmonic generation (THG) from mechanically exfoliated franckeite thin flakes are investigated. The observed highly anisotropic Raman modes and THG emission patterns originate from the low-symmetry crystal structure of franckeite induced by the lattice incommensurability between two constituent stacked layers. The thickness-dependent anisotropic THG response is further analyzed to retrieve the third-order nonlinear susceptibility for franckeite crystal. The results discussed herein not only provide new insights in engineering the nonlinear light–matter interactions in natural vdW heterostructures, but also develop a testbed for designing future miniaturized quantum photonics devices and circuits based on such heterostructures.

Section: Resultsmentioning

confidence: 99%

Naturally occurring layered mineral franckeite with anisotropic Raman scattering and third-harmonic generation responses

Tripathi

2021

Sci Rep

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“…Thereby, only four non‐zero elements

χ_{11}

χ_{18}

χ_{22}

, and

χ_{29}

will contribute to the in‐plane THG emission process. The electric field components of THG emission and the THG intensity can then be written as: [ 40 ]

E^{((), 3 ω)} = [\begin{matrix} E_{x}^{((), 3 ω)} \\ E_{y}^{((), 3 ω)} \\ E_{z}^{((), 3 ω)} \end{matrix}] \propto ε_{0} E^{3} [\begin{matrix} χ_{11} \cos^{3} θ + 3 χ_{18} \cos θ \sin^{2} θ \\ χ_{22} \sin^{3} θ + 3 χ_{29} \sin θ \cos^{2} θ \\ 0 \end{matrix}]

I_{x}^{((), 3 ω)} \propto {((), χ_{11} \cos^{3} θ + 3 χ_{18} \cos θ \sin^{2} θ)}^{2}

I_{y}^{((), 3 ω)} \propto {((), χ_{22} \sin^{3} θ + 3 χ_{29} \sin θ \cos^{2} θ)}^{2}

…”

Section: Resultsmentioning

confidence: 99%

“…[38] Here, the 0°and 90°directions are identified as the a-axis and b-axis of getchellite crystal, [39] for further probing the anisotropic linear and nonlinear optical responses of the crystal. [38][39][40]…”

Section: Raman Spectroscopy Characterization Of Getchellite Crystalmentioning

confidence: 99%

Van der Waals Layered Mineral Getchellite with Anisotropic Linear and Nonlinear Optical Responses

Tripathi

Laser & Photonics Reviews

2021

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Ultrathin ternary 2D materials have recently gained significant attention in the context of tailoring physical properties of materials via stoichiometric variation, which are crucial to many applications in optoelectronics, thermoelectrics, and nanophotonics. Herein, sulfide mineral getchellite is identified as a new type of ternary layered material and large‐area getchellite thin flakes are prepared through mechanical exfoliation. The highly anisotropic linear and nonlinear optical responses of getchellite thin flakes facilitated by the reduced in‐plane crystal symmetry are reported, including anisotropic Raman scattering, wavelength‐dependent linear dichroism transition, and anisotropic third‐harmonic generation (THG). Furthermore, the third‐order nonlinear susceptibility for getchellite crystal is retrieved from the thickness‐dependent THG emission. The demonstrated strong anisotropic linear and nonlinear optical properties of van der Waals layered getchellite will have implications for future technological innovations in photodetectors, optical sensors, nonlinear optical signal processors, and other on‐chip photonic device prototypes.

“…The lattice orientation of the anisotropic crystal system of nagyágite can be determined through angle‐resolved polarized Raman spectroscopy. Previously, this technique has been used for other monoclinic crystal systems such as GeAs [ 31 ] and MoTe 2 . [ 32 ] Figure 3b,c are contour color maps of the Raman intensity variation of the parallel and perpendicular polarization components as a function of the incident polarization angle (θ) with respect to the x ‐axis (θ = 0°).…”

Section: Resultsmentioning

confidence: 99%

Naturally Occurring 2D Heterostructure Nagyágite with Anisotropic Optical Properties

Dasgupta

2021

Adv Materials Inter

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a wide range of applications under the umbrella of one single material. [9][10][11][12][13][14] In addition to the focused direction of the artificial stacking of 2D material layers to fabricate heterostructures, the exfoliation of natural layered minerals consisting of alternating material building blocks has also come into the foray as an efficient way of creating ultrathin vdW heterostructures. Recently, it has been demonstrated that natural vdW minerals such as franckeite [15][16][17] and cylindrite [18] composed of alternating PbS-and SnS 2 -like layers can be exfoliated to a few layer thicknesses for realizing diverse optoelectronic and optical applications such as photodetection, linear dichroism, nonlinear harmonic generation, [19] and large Kerr nonlinearity. [20]