| Quantum dots glass materials are focused on nonlinear optics due to their excellent third-order nonlinear optical properties and potential applications in information and photoelectron technology. At present, reports on the glasses containing the various kinds of bismuth (metallic Bi, Bi2O3, and Bi2S3 are affiliated with VA-VIA group) quantum dots are still fewer in the field of the third-order nonlinear optical properties. For this purpose, the paper puts forward the sodium borosilicate glasses containing the various kinds of bismuth (metallic Bi, Bi2O3, and Bi2S3) quantum dots as research object, and the systematic researches on the series of quantum dots glasses have been focusing on the preparation, microstructure characterization, and the third-order nonlinear optical properties. Namely, a facile and effective preparation process is employed to realize the preparation of the series of quantum dots glasses, and microstructures of the glasses are investigated by a variety of techniques. Furthermore, Z-scan technique is used to measure the third-order nonlinear optical properties of the glasses. The parameters of the third-order nonlinear refraction and nonlinear absorption coefficient obtained reveal that the series of the glasses exhibit many excellent propeties in nonlinear optics. It could provide theoretical and practical foundation for further application in nonlinear optics. To the above research essentials proposed, the main research contents in this paper are summarized as follows:(1) The sodium borosilicate glasses containing metallic Bi, Bi2O3, and Bi2S3 quantum dots are prepared by employing both sol-gel and atmosphere control methods. The process feasibility is investigated by means of Differential scanning calorimetry and thermogravimetric analysis (DSC-TGA), Fourier infrared spectroscopy (FT-IR), X-ray powder diffractometer (XRD), etc. The process route is as follows:firstly, the stiff gel is heated in oxygen (O2) atmosphere at a rate of 10℃/hr up to 450℃, and kept 10 hr at this temperature to remove organic substance and decompose bismuth nitrate. Secondly, the aerogel is exposed to dry hydrogen (H2) to form metallic Bi at 450℃for 10 hr. Finally, the aerogel is heated in nitrogen (N2) atmosphere at a rate of 10℃/hr up to 600℃, and kept 10 hr at this temperature. The sodium borosilicate glass containing metallic Bi quantum dots will be obtained. Similarly, the sodium borosilicate glasses containing Bi2O3 and Bi2S3 quantum dots are also be obtained by the conversion among hydrogen (H2), oxygen (O2), and sulfuretted hydrogen (H2S) atmospheres. Namely, after the aerogel is exposed to dry hydrogen (H2) to form metallic Bi quantum dots at 450℃for 10 hr, hydrogen (H2) atmosphere is replaced by oxygen (O2) or sulfuretted hydrogen (H2S) atmosphere, and continue heating at 450℃for 10 hr to form Bi2O3 or Bi2S3 quantum dots. Subsequently, the aerogel treated by oxygen (O2) or sulfuretted hydrogen (H2S) atmosphere is still heated in nitrogen (N2) atmosphere at a rate of 10℃/hr up to 600℃, and kept 10 hr at this temperature. Finally, the sodium borosilicate glasses containing Bi2O3 and Bi2S3 quantum dots are also obtained.(2) The emphasis is mainly placed on microstructures and the third-order nonlinear optical properties of the sodium borosilicate glass containing Bi2S3 quantum dots in this paper. X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) are employed to characterize microstructures of the glass. The results show that Bi2S3 quantum dots in orthorhombic crystal system with regular spherical shape have formed uniformly in the sodium borosilicate glass, and the size of these Bi2S3 quantum dots ranges from several to over thirty nanometers. Meanwhile, the size of these Bi2S3 quantum dots is less than Bohr radius and the band gap Eg estimated by absorption spectrum shows an obvious red shift in comparison with the bulk Bi2S3, indicating that a significant quantum confinement effect will occur in the glass. Furthermore, Z-scan technique is employed to measure the third-order nonlinear optical parameters of the glass at 770 and 800 nm. The magnitudes of the parameters including the third-order nonlinear refractive indexγ, absorption coefficientβ, and susceptibilityχ(3) are determined to be～10-16 m2W-1,～10-9-10-8mW-1, and 10-10 esu, respectively. The results indicate that the glass exhibits very strong third-order nonlinear optical properties. Quantum confinement effects, thermal effects, and the third-order nonlinear optical absorption effect are several important affecting factors for the third-order nonlinear optical properties of the glass. In addition, the transitions from reverse saturable absorption to saturable absorption will occur with the increase of the excited light intensities.(3) The emphasis is mainly placed on microstructures and the third-order nonlinear optical properties of the sodium borosilicate glass containing Bi2O3 quantum dots in this paper. X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) are employed to characterize microstructures of the glass. The results show that the Bi2O3 quantum dots have formed uniformly in the sodium borosilicate glass, and the size of these quantum dots in monocilinic crystal system is usually less than 10 nm. The band gap Eg estimated by absorption spectrum shows an obvious red shift in comparison with the bulk Bi2O3, indicating that a significant quantum confinement effect will occur in the glass. Under the different light irradiance, the third-order nonlinear optical parameters of the glass are measured by Z-scan technique at 800 nm. The magnitudes of the parameters including the third-order nonlinear refractive indexγ, absorption coefficientβ, and susceptibilityχ(3) are determined to be～10-16 m2W-1,～10-9-10-8 mW-1, and 10-10 esu, respectively. The results indicate that the glass exhibits very strong third-order nonlinear optical properties. Moreover, the transitions from saturable absorption to reverse saturable absorption will occur with the increase of the excited light intensities. It shows that the glass will have a great potential in the field of nonlinear optics, such as optical limiters, etc. Meanwhile, quantum confinement effects, thermal effects, and the third-order nonlinear optical absorption effect are several important affecting factors for the third-order nonlinear optical properties of the glass.(4) The emphasis is mainly placed on microstructures and the third-order nonlinear optical properties of the sodium borosilicate glass containing metallic Bi quantum dots in this paper. X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) are employed to characterize microstructures of the glass. The results show that metallic Bi quantum dots in hexagonal crystal system with regular spherical shape have formed uniformly in the sodium borosilicate glass, and the size of these metallic Bi quantum dots ranges from several to over thirty nanometers. The blue-shift of the absorption edge indicates a significant quantum confinement effect in the glass. The third-order nonlinear optical parameters of the glass are measured by Z-scan technique at 800 nm. The magnitudes of the parameters including the third-order nonlinear refractive indexγ, absorption coefficientβ, and susceptibilityχ(3) are determined to be～10-17 m2W-1,～10-9 mW-1, and 10-11 esu, respectively. The results indicate that the glass exhibits very strong third-order nonlinear optical properties. Quantum confinement effects, thermal effects, and the third-order nonlinear optical absorption effect are several important affecting factors for the third-order nonlinear optical properties of the glass.
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