Ultrafast nonlinear optical properties of two-dimensional semiconductors

Jun Wang

Key Laboratory of Materials for High Power Lasers, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China

jwang@siom.ac.cn

ABSTRACT

Owing to the specific two-dimensional (2D) confinement of electron motion and the absence of interlayer perturbation, 2D semiconductors possess unique optoelectronic properties and has become a research hot-spot in recent years. Whereas the electronic and luminescent properties of 2D transition metal dichalcogenide (TMDC) nanosheets, say, MoS₂, MoSe₂, WS₂, etc., have been generating much research interest, the ultrafast nonlinear optical (NLO) properties remain largely unexplored. Realized that the sizable and thickness-dependent bandgap offers TMDCs a huge potential in the development of photonic devices with high performance and unique functions, we studied extensively the ultrafast NLO property of a range of TMDC nanosheets. 2D TMDC nanosheets with high-quality layered nanosheets were prepared using liquid-phase exfoliation technique. Ultrafast saturable absorption, two-photon absorption, ultrafast nonlinear photoluminescence were observed from the 2D nanostructures. The exciting results open up the door to 2D photonic nano-devices, such as optical switches, pulse shaping devices, mode-lockers, optical limiters, etc., capable of ultrafast response and broadband tunability.

References

1.      N. Dong, J. Wang et al. Optical limiting and theoretical modelling of layered transition metal dichalcogenide nanosheets, arXiv:1503.02257 (2015).

2.      Y. Li, J. Wang et al. Giant two-photon absorption in monolayer MoS2, arXiv:1503.02259 (2015).

3.      S. Zhang, J. Wang, et al. Direct observation of degenerate two photon absorption and its saturation of WS2 and MoS2 monolayer and few-layer films, arXiv:1503.02258 (2015).

4.      G. Wang, J. Wang, et al. Tunable nonlinear refractive index of two-dimensional MoS2, WS2 and MoSe2 nanosheet dispersions, Photonics Research, (2015).

5.      K. Wu, J. Wang, et al. 463 MHz Fundamental Mode-locked Fiber Laser Based on Few-layer MoS2 Saturable Absorber, Optics Letters, 40, 1374 (2015).

6.      X. Zhang, J. Wang, et al. Facile fabrication of wafer-scale MoS2 neat films with enhanced third-order nonlinear optical performance, Nanoscale, 7, 2978 (2015).

7.      K. Wang, J. Wang, et al. Broadband ultrafast nonlinear absorption and nonlinear refraction of layered molybdenum dichalcogenide semiconductors, Nanoscale, 6, 10530 (2014).

8.      K. Wang, J. Wang, et al. Ultrafast saturable absorption of two-dimensional MoS2 nanosheets, ACS Nano, 7, 9260 (2013).