Centre wavelength explained

The centre wavelength is the power-weighted mean wavelength:

λ _{c} = (1)/(P _{total}) \int p( λ ) λ d λ ,

and the total power is

P _{total} = \int p( λ ) d λ ,

where

p( λ ) 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( λ ) is higher than a fraction of its maximum.

See also

• Dominant wavelength