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arXiv · 1711.02982

Third-order Optical Nonlinearity in Two-dimensional Transition Metal Dichalcogenides

Sina Khorasani
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Abstract

We present a detailed calculation of the linear and nonlinear optical response of four types of monolayer Two-Dimensional (2D) Transition-Metal Dichalcogenides (TMDCs), having the formula $\textrm{MX}_2$ with M=Mo,W and X=S,Se. The calculations are based on 6-band tight-binding model of TMDCs, and then performing a semiclassical perturbation analysis of response functions. We numerically calculate the linear $χ_{μν}^{(1)}(-ω;ω)$ and nonlinear surface susceptibility tensors $χ_{μνζη}^{(3)} (-ω_Σ;ω_r,ω_s,ω_t)$ with $ω_Σ=ω_r+ω_s+ω_t$. Both non-degenerate and degenerate cases are studied for third-harmonic generation and nonlinear refractive index, respectively. Computational results obtained \textit{with no external fitting parameters} are discussed regarding two recent reported experiments on ${\rm MoS}_2$, and thus we can confirm the extraordinarily strong optical nonlinearity of TMDCs. As a possible application, we demonstrate generation of a $\fracπ{4}-$rotated squeezed state by means of nonlinear response of TMDCs, in a silica micro-disk resonator covered with the 2D material. Our proposed method will enable accurate calculations of nonlinear optical response, such as four-wave mixing and high-harmonic generation in 2D materials and their heterostructures, thus enabling study of novel functionalities of 2D photonic integrated circuits.

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Sina Khorasani. 2018-08-27. Third-order Optical Nonlinearity in Two-dimensional Transition Metal Dichalcogenides. https://doi.org/10.1088/0253-6102%2F70%2F3%2F344

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