$rm Lux$ to $rm W/m^2$ conversion?

For a physics project, I’m planning to investigate the relationship between the number of slits in a diffraction grating and the intensity of the central maxima. The light meter which I’m planning to use to measure the intensity gives me a result in LUX.

I know the wavelength of the red laser light which I’m using is approximately 550 nm. I’m wondering if it’s at all possible to use a conversion to change the lux value in W/m^2?

If not, is there any other way I could possibly measure the intensity of the central maxima that would give me a result in w/m^2?