monochromaticity
Noun
Meaning
monochromaticity (uncountable)
the degree to which something is monochromatic
Examples
Although temporal coherence implies monochromaticity, there are lasers that emit a broad spectrum of light or emit different wavelengths of light simultaneously.
This gives laser light its characteristic coherence, and allows it to maintain the uniform polarization and often monochromaticity established by the optical cavity design.