Centre wavelength

The centre 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