Broadband femtosecond nonlinear optical properties of CsPbBr_3 perovskite nanocrystals
Abstract
We report the broadband nonlinear optical (NLO) properties of CsPbBr3 perovskite films achieved from colloidal nanocrystals prepared following a room temperature and open atmosphere anti-solvent precipitation method. The NLO studies were performed on the films of nanocubes (NCs) and nanorods (NRs) using the Z-scan technique with 1 kHz femtosecond pulses at 600, 700, and 800 nm. Large two-photon absorption cross sections (∼105 GM) were retrieved by fitting the open-aperture Z-scan data. Strong third-order NLO susceptibility (∼10−10 esu) was observed in these films. At higher peak intensities a switching of sign (in both NCs and NRs) in the real and imaginary parts of the NLO susceptibility was observed from the studies on these CsPbBr3 nanocrystals. The obtained NLO coefficients clearly suggest that these materials are promising for ultrafast photonic applications.