Instead, holmium oxide is used to calibrate instruments in the visible and near-infrared (NIR) regions of the electromagnetic spectrum. Here's why:
* Sharp Absorption Bands: Holmium oxide exhibits sharp, well-defined absorption bands in the visible and NIR regions. These bands are highly reproducible and serve as reliable reference points for wavelength calibration.
* Stable and Inert: Holmium oxide is a stable and inert material, making it suitable for long-term use in calibration standards.
* Widely Available: It's readily available in various forms, including solutions and solid filters, making it accessible for calibration purposes.
Calibration in the UV Region:
For UV calibration, materials like mercury, deuterium, and xenon lamps are commonly used as primary standards. These lamps emit specific wavelengths in the UV region that serve as reference points for instrument calibration.
In summary, while holmium oxide is a valuable material for visible and NIR calibration, it's not used for UV calibration.
