Broadband nonlinear optical response of monolayer MoSe2 under ultrafast excitation

Zhonghui Nie, Chiara Trovatello, Eva A. A. Pogna, Stefano Dal Conte, Paulo B. Miranda, Edmund Kelleher, Chunhui Zhu, Ion Crisitan Edmond Turcu, Yongbing Xu, Kaihui Liu, Giulio Cerullo, Fengqiu Wang
2018 Applied Physics Letters  
Abstract: Due to their strong light-matter interaction, monolayer transition metal dichalcogenides (TMDs) have proven to be promising candidates for nonlinear optics and optoelectronics. Here, we characterize the nonlinear absorption of CVD-grown monolayer MoSe 2 in the 720-810 nm wavelength range. Surprisingly, despite the presence of strong exciton resonances, monolayer MoSe 2 exhibits a uniform modulation depth of ~80±3% and saturation intensity of ~2.5±0.4 MW/cm 2 . In addition, pump-probe
more » ... dition, pump-probe spectroscopy is performed to confirm the saturable absorption and reveal the photocarrier relaxation dynamics over hundreds of picoseconds. Our results for the first time unravel the unique broadband nonlinear absorptive behavior of monolayer MoSe 2 under ultrafast excitation and highlight the potential of using monolayer TMDs as broadband ultrafast optical switches with customizable saturable absorption characteristics.
doi:10.1063/1.5010060 fatcat:2tacefcwzzha5jvwurlxoy422y