Centroid wavelength

The centroid wavelength is the power-weighted mean wavelength:

${\lambda }_{\text{c}}=\frac{1}{P_{\text{total}}}\int p(\lambda )\lambda d\lambda ,$

and the total power is

$P_{\text{total}}=\int p(\lambda )d\lambda ,$

where $p(\lambda )$ is the power spectral density, for example in W/nm.

The above integrals theoretically extend over the entire spectrum, however, it is usually sufficient to perform the integral over the spectrum where the spectral density $p(\lambda )$ is higher than a fraction of its maximum.

See also

• Dominant wavelength