I agree that it will help, to the extent that it counters diffraction of the beam whilst is in the atmosphere, hence it having "limited" application rather than

I agree that it will help, to the extent that it counters diffraction of the beam whilst is in the atmosphere, hence it having "limited" application rather than no application. Diffraction still happens in a vacuum. The beam spreads, so photons are lost by not falling on the detector. The waveguide effect would counteract scattering to some degree. Even then, wouldn't scattering emit photons in random directions, meaning that the majority of scattered photons would be moving at too great an angle to the high/low density boundary to be refracted back into the beam?