I think the equation given does give units in watts/m^2? Unless I'm missing something, power has the units of W, and the only dimensions on the bottom of the eq

I think the equation given does give units in watts/m^2? Unless I'm missing something, power has the units of W, and the only dimensions on the bottom of the equation are the radius, which is meters. Because it's r^2, the result is in W/m^2. For a non-directional beam, it would be P/(4.pi.r^2).