Sodium deoxycholate surfactant selected large-diameter single-walled carbon nanotubes (∼1.6 nm): Characterization and nonlinear optical properties

Abstract In the present work, we proposed a strategy to select the single-walled carbon nanotubes (SWCNTs) with a relatively large diameter (∼1.6 nm) with a sodium deoxycholate (SDC) surfactant. Both the Raman spectrum and the transmission electron microscopy (TEM) image confirmed the successful sorting of the large diameter (∼1.6 nm). In addition, the prepared large-diameter SWCNTs exhibited the wide absorption band, implying the possible wideband nonlinear optical properties. A conventional open-aperture Z-scan measurement was implemented to investigate typical saturable absorption performance at 1.3 and 1.9 μm. As a proof of the excellent nonlinear saturable absorption, passively Q-switched lasers were demonstrated with the prepared large-diameter SWCNTs based saturable absorber, producing the minimum pulse duration of 335 ns. Our work reversed that the saturable absorption of SWCNTs can extend to the Mid-IR regime by sort the proper diameter.