Structured cadmium sodium diborate glass optical bandpass filters doped with copper oxide: Impact of cadmium oxide

Glasses of cadmium sodium diborate doped with copper oxide were created. These glasses have optical filters in the ultraviolet and visible wavelength ranges. Cadmium oxide (CdO) is used to regulate the properties of glass and the range of optical filters. The 10.8 mol% CdO sample has a broad visible-near-infrared blocking region spanning 640–900 nm. Glass has triangular (BO3) and tetragonal (BO4) borate groups that are linked together by B–O–B bridges. When the CdO content increased from 10 to 13.3 mol%, the N4 ratio increased from 0.423 to 0.568, indicating the dominance of the BO4 units. As a result, the glass density (D) rose from 2.876 to 3.113 g/cm3, while the boron-boron (dB-B) separation fell from 3.731 to 3.603 Å. The optical transition (Eg) decreased slightly as CdO increased, from 3.107 eV to 3.021 eV, and the refractive index varied from 1.515 to 1.577 at 589 nm. [Display omitted] •The properties of sodium borate glass doped with CuO are controlled by CdO.•As CdO increased from 10 to 13.3 mol%, the N4 ratio increased from 0.423 to 0.568.•Where the CdO increases, the density values increase from 2.876 g/cm3 to 3.113 g/cm3.•The CdO content slightly lowers the optical transition from 3.107 eV to 3.021 eV.•The glass has a significant optical blocking region of 640–900 nm at 10.8 mol% CdO.