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

Antti Säynätjoki, Lasse Karvonen, Habib Rostami, Anton Autere, Soroush Mehravar, Antonio Lombardo, Robert A. Norwood, Tawfique Hasan, Nasser Peyghambarian, Harri Lipsanen, Khanh Kieu, Andrea C. Ferrari, Marco Polini, Zhipei Sun

Research output: Contribution to journalArticlepeer-review

162 Scopus citations


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.

Original languageEnglish (US)
Article number893
JournalNature communications
Issue number1
StatePublished - Dec 1 2017

ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)


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