Re: Calling Isaac Newton...
I await with interest the design of your zero divergence laser.
All lasers have divergence, even if it's measured in microradians. To be exact, the minimum divergence of any laser beam is lambda/(pi * beam radius). Once the diameter of the beam exceeds the area of your sail, the inverse square law applies. The smaller you try to make the initial beam diameter, the larger the divergence angle.
Lasers are only constant diameter for distances which are short on solar system scales.
The picture is me extracting my old notes on laser physics from when I worked for an optics company.
Biting the hand that feeds IT
