Abbe number
Sign in to saveAlso known as Abbe diagram, V-number, Constringence, Abbe value
material dispersion property
~8 min read
Encyclopedic overview
In optics and lens design, the Abbe number, also known as the Vd-number or constringence of a transparent material, is an approximate measure of a material's dispersion (change in refractive index as a function of wavelength), with high Vd values indicating low dispersion. It is named after Ernst Abbe (1840–1905), the German physicist who defined it. The term Vd-number should not be confused with the normalized frequency in fibers.
Index of refraction as a function of wavelength for SF11 flint glass, BK7 borosilicate crown glass, and fused quartz. Inset shows two sample calculations for Abbe numbers of SF11.
Excerpted from Wikipedia’s “Abbe number” article, available under the CC BY-SA 4.0 licence.