Passively Q-switched laser with specific chiral SWCNTs selected by N-CS as saturable absorber at 1 μm

The single-wall carbon nanotubes (SWCNTs) with the specific chirality (6, 5) and (7, 5) were sorted out by the density gradient ultracentrifugation (DGU) method. 2D photoluminescence excitation-emission map and the Raman spectrum confirmed the successful chirality-selection. The nonlinear optical performance of the chirality-selected SWCNTs was investigated by an open-aperture Z-scan setup. By employing the prepared SWCNTs saturable absorber (SWCNTs-SA), the minimum pulse duration of 115 ns with a pulse repetition rate of 550 kHz was obtained in the passively Q-switched (PQS) laser operation.