Fig. 2.
Open-aperture z-scan results of the biological synthesized tellurium samples. a Experimental results with fs pulses, 800 nm. Bio-Te-PmPV (solid circles); PmPV (hollow squares). Solid lines: fitted z-scan curves using equation (1); Dashed lines are for visual guide. b, c Experimental results with 340 fs laser at 515 nm (b) and 1030 nm (c). d Saturated intensity Isat of Bio-Te-PmPV and graphene dispersion as functions of the laser intensity at 1030 nm and 515 nm. e, f Mid-infrared open z-scans of Bio-Te and graphene polymethyl methacrylate (PMMA) films at 2.5 μm and 2.8 μm wavelengths, showing better saturable absorptive responses of Bio-Te than those of graphene