CUED Publications database

Ultra-strong nonlinear optical processes and trigonal warping in MoS2 layers.

Säynätjoki, A and Karvonen, L and Rostami, H and Autere, A and Mehravar, S and Lombardo, A and Norwood, RA and Hasan, T and Peyghambarian, N and Lipsanen, H and Kieu, K and Ferrari, AC and Polini, M and Sun, Z (2017) Ultra-strong nonlinear optical processes and trigonal warping in MoS2 layers. Nat Commun, 8. 893-.

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Nonlinear optical processes, such as harmonic generation, are of great interest for various applications, e.g., microscopy, therapy, and frequency conversion. However, high-order harmonic conversion is typically much less efficient than low-order, due to the weak intrinsic response of the higher-order nonlinear processes. Here we report ultra-strong optical nonlinearities in monolayer MoS2 (1L-MoS2): the third harmonic is 30 times stronger than the second, and the fourth is comparable to the second. The third harmonic generation efficiency for 1L-MoS2 is approximately three times higher than that for graphene, which was reported to have a large χ (3). We explain this by calculating the nonlinear response functions of 1L-MoS2 with a continuum-model Hamiltonian and quantum mechanical diagrammatic perturbation theory, highlighting the role of trigonal warping. A similar effect is expected in all other transition-metal dichalcogenides. Our results pave the way for efficient harmonic generation based on layered materials for applications such as microscopy and imaging.Harmonic generation is a nonlinear optical process occurring in a variety of materials; the higher orders generation is generally less efficient than lower orders. Here, the authors report that the third-harmonic is thirty times stronger than the second-harmonic in monolayer MoS2.

Item Type: Article
Divisions: Div B > Solid State Electronics and Nanoscale Science
Div B > Photonics
Depositing User: Cron Job
Date Deposited: 17 Jul 2017 19:07
Last Modified: 20 Jul 2018 20:22