and the distinction you make is kinda pointless
It's not just the power level at the fusion target that drives the size of an inertial confinement (pure laser-driven) fusion trigger. It's the way in which that power is delivered. In the case of NIF, 192 beams have to converge on the target from 192 different directions within picoseconds of each other, and the size, focus, and power levels of those 192 beams have to be coordinated and balanced with insane precision. If not, various instabilities (Richtmeyer-Meshkov, Rayleigh-Taylor, etc.) develop in the target that prevent it from fusing. NIF and every other ICF experiment has failed to achieve ignition for these reasons.
the main reason it is so bulky is because these systems require great bulk (it uses Xenon flashbulbs for the initial laser pulse.. it's not even solid state like the LaWS!)
This is apples and oranges. The types and the precision of the lasers needed to punch a hole in some thin aluminum flying through the air are radically different from the types and the precision of the lasers needed to compress light atomic nuclei until they fuse. It's like comparing my driving glasses to an electron microscope. Or the accuracy of a handgun at 10 yards to the accuracy of orbit insertion by a spacecraft at Mars starting from Earth. Completely understates the problem.
(Disclosure: Many moon ago, I worked on a project involving solid state lasers for space launch, which, although tougher than shooting down UAVs, was still many orders of magnitude easier than fusing atomic nuclei.)
it also wastes a ridiculous amount of power in converting frequencies.. they start with IR but have to convert it to UV.
I'm sure the folks at Lawrence Livermore would love to hear from you about their various inefficiencies and your ideas for scaling down their multi-football field-sized facility while maintaining the precision needed to achieve laser ICF. ::)
with BT technology you can make a solid state UV beam generator able to produce a one time pulse of that power fairly easily.
We can't achieve pure laser-driven fusion -- inertial confinement fusion -- just by pointing a powerful enough laser at a target. The resulting plasma just dissipates before the onslaught of the wavefront. The target can't just be heated up; it has to be _inertially confined_ by the photons and compressed until the nuclei fuse. That's what drives the multiple football field-sized devices and techniques used at NIF and other ICF sites.
Unless the physics of BT optics and nuclear fusion work differently (and they may), the same hurdles to achieving ICF (aka "laser-driven pure fusion"), nevertheless scaling it down from multi-football-field sized facilities to grenade-sized devices, would apply.
FWIW...
