Study on the Third-order Optical Nonlinear Absorption Properties of Bi_2O_3 Nanocrystals Glass

The sodium borosilicate glass containing Bi 2 O 3 nanocrystals was synthesized by employing both Sol-Gel and atmosphere control methods.Morphology and microstructure of the Bi 2 O 3 nanocrystals doped in the sodium borosilicate glass were characterized by means of X-ray powder diffraction(XRD),X-ray photoelectron spectroscope(XPS),transmission electron microscope(TEM),energy dispersion X-ray spectra(EDX),scanning transmission electron microscope(STEM),high-resolution transmission electron microscope(HRTEM),and selected-area electron diffraction(SAED).Meanwhile,the third-order nonlinear optical absorption properties of the Bi 2 O 3 nanocrystals glass were investigated by means of the femtosecond open-aperture Z-scan technique under the different excited light intensities at a wavelength of 800 nm.The results show that the Bi 2 O 3 nanocrystals are formed in the sodium borosilicate glass matrix,with dimension less than 10 nm.Moreover,the transformation from saturable absorption to reverse saturable absorption will occur with the increase of the excited light intensities in the glass.Furthermore,the calculated magnitude of the third-order nonlinear susceptibility χ(3) ranges from 10-19 to 10-18 m 2 /V 2 in the glass.The results indicate that the glass exhibits the excellent nonlinear optical properties,which have potential application in the field of nonlinear optics such as optical limiters,etc.