Third-order Nonlinear Optical Properties of Bi_2S_3 Nanocrystals Embedded in Sodium Borosilicate Glass

Bi2S3 nanocrystals(1wt%) embedded in sodium borosilicate glass were synthesized through Sol-Gel process.The morphology and microstructure of Bi2S3 nanocrystals in 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) and high-resolutions TEM(HRTEM).Furthermore,the third-order nonlinear optical properties of the glass were measured by femtosecond Z-scan technique at a wavelength of 770 nm.The results show that the size of Bi2S3 nanocrystals in sodium borosilicate glass usually ranges from 10 to 30 nm,and the Bi2S3 nanocrystals are determined to be of the orthorhombic phase.The third-order nonlinear optical refractive index γ,absorption coefficient β and susceptibility χ(3) of the glass are determined to be 5.90×10 16 m2/W,7.35×10 9 m/W and 4.55×10 18 m2/V2,respectively.Thereinto,the third-order optical nonlinear susceptibility χ(3) of the glass is four orders of magnitude greater than un-doped glass(χ(3)= 1.09×10 22 m2/V2).It is clear that the third-order nonlinear optical properties of the glass will be improved greatly with an increase of the Bi2S3 content.