Here are the lasers from a 1970s laser confinement experiment: https://en.wikipedia.org/wiki/Inertial_confinement_fusion#/media/File:NOVA_laser.jpg
I can't really judge, but this sure looks like a lot of energy overhead to me! I suppose a rail gun would have impart more energy to the sample with less overhead. There is no way you could use one as a portable, ship-mounted weapon otherwise. - Jed
