{{short description|Power-weighted mean wavelength}}
The '''centroid wavelength''' is the power-weighted mean wavelength:<ref>{{Cite journal |last=Hieda |first=Keisuke |last2=Maruyama |first2=Tomoyuki |last3=Narusawa |first3=Fumio |date=2019-10-04 |title=The Importance of Centroid Wavelength for the Image Quality Evaluation of Laser Displays |url=https://sid.onlinelibrary.wiley.com/doi/10.1002/sdtp.13724 |journal=SID Symposium Digest of Technical Papers |language=en |volume=50 |issue=S1 |pages=1002–1004 |doi=10.1002/sdtp.13724 |issn=0097-966X|url-access=subscription }}</ref>
: <math>\lambda_\text{c} = \frac{1}{P_\text{total}} \int p(\lambda) \lambda\, d\lambda,</math>
and the total power is
: <math>P_\text{total} = \int p(\lambda) \,d\lambda,</math>
where <math>p(\lambda)</math> 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 <math>p(\lambda)</math> is higher than a fraction of its maximum.
==See also== <!--* Peak wavelength --> * Dominant wavelength
==References== {{reflist}}
Category:Waves
{{optics-stub}}