Fig. 1. Experimental setup for the Z-scan technique.

Fig. 2. (a) XRD patterns and (b) PL emission spectra of CsPbCl1.5Br1.5 NCs glasses under different treatment temperature excited by femtosecond pulses at 365 nm.

Fig. 3. OA Z-scan results of CsPbCl1.5Br1.5 NCs glasses with different treatment temperatures. (a) Under pump intensity 25.5  GW/cm2 at a wavelength of 800 nm and (b) under pump intensity 217  GW/cm2 at a wavelength of 1300 nm. (The balls are the experimental data, and the solid lines are fitting curves.) The fitting results of (c) β and (d) γ of CsPbCl1.5Br1.5 NCs glass with different treatment temperatures. (Inset, the schematic of a two-level model.)

Fig. 4. (a) OA Z-scan curves and (b) corresponding fitting results of β (black ball), Imχ(3) (pink), and FOM (blue) of the CsPbCl1.5Br1.5 NCs glass at the wavelength of 800 nm with different incident pump intensity.

Fig. 5. OA Z-scan results of CsPbClxBr3−x (x=1, 1.5, 2) NCs glasses. (a) Under pump intensity 178  GW/cm2 at a wavelength of 800 nm and (b) under pump intensity 535  GW/cm2 at a wavelength of 1300 nm. (The balls are the experimental data, and the solid lines are fitting curves.) (c) PL emission spectra of CsPbClxBr3−x (x=1, 1.5, 2) NCs glasses for 500°C treatment temperature excited by femtosecond pulses at 365 nm; (d) fitting the results of 2PA coefficient (β, purple bar) and 3PA coefficient (γ, red bar) obtained in (a) and (b), respectively.

Fig. 6. (a) Transmission electron microscopy (TEM) images of CsPbCl_xBr_3-x (x = 1, 1.5, 2) NCs and (b) high-resolution TEM images of CsPbCl_1.5Br_1.5 NCs.

Fig. 7. (a) Amplified spontaneous emission (ASE) measurement on CsPbCl_1.5Br_1.5 NCs glass under an 800 nm pulsed laser at room temperature and (b) corresponding full-width at half-maxima (FWHM) and output as a function of incident pump intensity.

Fig. 8. (αhυ)²-hυ plot of CsPbCl_xBr_3-x (x=1, 2, 3) NCs glass.

Fig. 9. Open-aperture Z-scan curves of the (a) CsPbCl₁Br₂ and (b) CsPbCl₂Br₁ NCs glasses at the wavelength of 800 nm with different incident pump intensity.