It is important to regularly re-calibrate spectrometers to ensure measurement accuracy. Wavelength reflectance standards offer an affordable and easy way of doing this.
To re-calibrate using a wavelength standard, the user simply measures the calibrated standard as if it were a sample. The standard provides a known peak wavelength and intensity at that wavelength. Comparing the value of the known standard to the spectrometer result allows the necessary instrument re-calibration to be identified.
Constant wavelength values are created through the addition of one or more rare earth oxides to a reflectance material. This oxide displays a sharp absorption spikes at one or more specific wavelengths. Complete absorption data is supplied with each standard. The standard my have one wavelength value or multiple values.
For example, Labsphere offers single wavelength standards of holmium oxide for UV-Vis-NIR calibrations, dysprosium oxide for NIR calibrations, and erbium oxide for Vis-NIR calibrations or all three for a multi-component wavelength standard for NIR reflectance spectrometer re-calibration.