This filter consists of a glass containing didymium oxide (a mixture of neodymium and praseodymium oxides) optically bonded to a neutral density filter. It is mounted stress-free within an anodised aluminium holder equipped with sliding window covers to protect the surface when not in use.
The device is designed for routine verification of both wavelength and absorbance accuracy in visible spectrophotometers. Characteristic didymium peaks serve as reliable wavelength reference points over the 430 to 890 nm spectral range, superimposed on a nominal 1 absorbance (1A) background provided by the neutral density component. Due to variations in glass melt, each filter is individually certified to ensure traceability and accuracy.
This filter consists of a glass containing didymium oxide (a mixture of neodymium and praseodymium oxides) optically bonded to a neutral density filter. It is mounted stress-free within an anodised aluminium holder equipped with sliding window covers to protect the surface when not in use.
The device is designed for routine verification of both wavelength and absorbance accuracy in visible spectrophotometers. Characteristic didymium peaks serve as reliable wavelength reference points over the 430 to 890 nm spectral range, superimposed on a nominal 1 absorbance (1A) background provided by the neutral density component. Due to variations in glass melt, each filter is individually certified to ensure traceability and accuracy.
