Z-scan traces of samples A to D under laser intensity of I0 = 3.54 × 1011 W/cm2 at the focal point. The open and closed Z-scan traces are shown in (a,b,c,d) and (e,f,g,h), respectively. Black squares are the experimental data and the solid lines are the fitting curves.
Zhang et al. Nanoscale Research Letters 2014 9:28 doi:10.1186/1556-276X-9-28