Light Wavelength

[EarlyPan]

Hi,
Has anyone ever attempted to measure the LUX at a specific wavelength, for example 630 nm? I,m thinking that if I could use a filter to pass only the light around that wavelength, which seems to be optimum for bloom, then I could compare the various light fixtures and types. No point in pouring on lots of light that the plants can't use, right? The same might be applied to the bluer light for plant growth.