What are wavelength standards?

Wavelength standards are precise reference points used to define specific wavelengths of light in various applications, such as spectroscopy and metrology. These standards, often derived from stable atomic or molecular transitions, enable accurate measurements and calibrations in scientific research and industry. Common examples include the wavelengths of certain laser lines and the emission lines of noble gases. By providing a reliable basis for comparison, wavelength standards ensure consistency and accuracy in optical measurements.