Figure 13. (
a) Nonlinear absorption of CH
3NH
3PbI
3 and CH
3NH
3PbI
3−xCl
x samples under irradiation of a 1064 nm pulsed laser. (
I) Experimental results and theoretical fitting for the nonlinear absorption of CH
3NH
3PbI
3. (
II) Experimental results and theoretical fitting for the nonlinear absorption of CH
3NH
3PbI
3−xCl
x. (
III) Experimental results and theoretical fitting for the nonlinear refractive index of CH
3NH
3PbI
3. (
IV) Experimental results and theoretical fitting for the nonlinear refractive index of CH
3NH
3PbI
3−xCl
x; (
b) Nonlinear absorption of CH
3NH
3PbI
3 and CH
3NH
3PbI
3−xCl
x samples in open aperture condition under irradiation of a 532 nm pulsed laser. (
I) Experimental results and theoretical fitting for the nonlinear absorption of CH
3NH
3PbI
3. (
II) Experimental results and theoretical fitting for the nonlinear absorption of CH
3NH
3PbI
3−xCl
x; Reprinted with permission from
[43]. Copyright 2016 American Chemical Society. (
c) (
I) SEM image of the perovskite, and the inset shows the cross-sectional SEM image. (
II) The linear transmittance spectrum of the perovskite. (
III) The nonlinear open aperture and (
IV) closed aperture/open aperture Z-scan measurement of the perovskite at 1562 nm, respectively; Reprinted with permission from
[45]. Copyright 2017 American Chemical Society. (
d) Nonlinear optical properties of CH
3NH
3PbI
3 perovskite nanosheets.
Z-scan profiles measured at (
I) 800 and (
III) 1030 nm. The normalized transmittance versus input peak intensity at (
II) 800 and (
IV) 1030 nm. The insets in panel b show the energy diagrams of the linear absorption and saturable absorption. (
V) Nonlinear absorption coefficient β as a function of nanosheet thickness. (
VI) Modulation depths of perovskite nanosheets with different thicknesses. Reprinted with permission from
[44]. Copyright 2017 AIP Publishing.