The Structural Investigation of a ZBLAN Glass by Vibrational Spectroscopy

Luu-Gen Hwa；Chen-Ke Shu

Chinese Journal of Physics

34卷5期（1996 / 10 / 01）

1270 - 1275

英文

The heavy metal fluoride glasses exhibit high transparency over the frequency range from the mid-IR to the near UV. .They also possess low refractive index, low material dispersion, low linear scattering loss, and good chemical durability. These properties make them the promising candidate for a wide variety of applications ranging from laser windows to infrared fiber optics. The structural investigations of a typical heavy metal fluoride glass, ZBLAN, by vibrational spectroscopy (multi-phonon edge absorption, infrared reflectivity and polarized Raman scattering measurements) were performed. From our study, we are able to understand the fundamental vibrational characteristics of this glass and the primary mechanisms influencing its infrared transparency. The LOTO vibrational pair splitting was observed for this glass by IR reflectivity measurement at different incident angle. We believe that this type of crystal-like behavior is related to frozen in density and concentration fluctuations in the glass structure during the glass formation. The low frequency Raman spectrum (10～100 cm-i) - the so called Boson Peak - was also studied for the same glass. The characteristic length scale (Structural Correlation Length) was calculated with the aid of Martin-Brenig model. The degree of disorder in the glass structure will be discussed in the light of the existing theory.