I agree. It would depend on the definition of "far-field" in this example, even for a quasi-Bessel beam there is a near region that maybe useful for this exampl

I agree. It would depend on the definition of "far-field" in this example, even for a quasi-Bessel beam there is a near region that maybe useful for this example given a large enough aperture. This paper [1] demonstrates the reduced power loss of a Bessel beam compared to a Gaussian for various target distances. For targeting GEO, a Bessel beam can be 75% the size of a Gaussian for the same halving of power-loss. In reality, I think a Gaussian beam is fine - and much simpler to engineer. [1] https://opg.optica.org/josaa/fulltext.cfm?uri=josaa-32-11-2066&id=331336 https://opg.optica.org/josaa/fulltext.cfm?uri=josaa-32-11-20...