摘要
Silver nanoparticle (AgNP) aqueous colloids with different surface plasmon resonance (SPR) frequencies were controllably synthesized by a facile and green chemical synthesis method. The obtained AgNPs with an average diameter of ~ 15 nm show a symmetrical SPR peak at ~ 400 nm. Another longitudinal SPR mode at ~ 520 nm occurs when increasing the amount of ethanol according to the ultraviolet-visible light spectra. The third-order nonlinear optical (NLO) absorption properties of the AgNP colloids were found to switch from two-photon absorption (TPA) to saturable absorption (SA) by tuning the SPR frequency using Z-scan technique with 340 fs pulses at 515 nm. When combined with two-dimensional (2D) MoS_(2), an enhanced SA response is observed for Ag/MoS_(2 )nanocomposites compared with the counterparts. The nonlinear absorption coefficient of Ag/MoS_(2) nanocomposites is about − (10.93 ± 0.6) × 10^(-2 )cm·GW^(−1), which is almost three times higher than that of MoS_(2). Our work has an instructive value in promoting the potential application of AgNPs and its nanocomposites in optoelectronic and photonic devices, such as optical limiting and ultrafast laser pulse generation.
基金
financially supported by the National Natural Science Foundation of China (NSFC) (Grant No. 51972318)
the Natural Science Foundation of Shanghai (Grant No. 19ZR1479300)
the Strategic Priority Research Program of Chinese Academy of Sciences (CAS) (Grant No. XDB16030700)