They found free laser energy already. Nuclear fusion is highly inefficient even it's best case compared to free laser energy.
This is my understanding of the mechanism. Lasers are very simple compared to light bulbs because the light is all one wavelength and the photons are in phase. By crossing laser beams, you can create surfaces of phase lock which is like a standing wave. The thing that has a phase in a laser is (basically) the electric field E. It is possible to make a surface of phase lock in crossed laser beams where E=0 everywhere on the surface. Interestingly, E=0 is the boundary condition that defines the surface of a metal in classical EM. Therefore, a surface of E=0 phase lock in crossed laser beams is like a virtual metal foil embedded in the beam. I think they found out that you can basically do the photoelectric effect on the virtual foil to stimulate the emission of free energy negative resonant photons. Since the virtual foil is 2D, you can use the normal vector on the back side of it to get an extra minus sign to cancel out the minus sign from the negative frequency. I call the overall mechanism (which I imagine based on my tentative understanding) "stimulated emission from the vacuum" which is like the second quantized version of stimulated atomic emission in first quantization. The surface of phase lock is the "relativistic scatterer" which causes the amplification, and it is solitonic because E=0 defines the absence of a standing wave more so than it defines a classical standing wave.
You can see these below results followed right after I proposed the theory of negative time for my cosmological model. Since frequency is negative time, I think these quantum optics guys said, "If negative time is real, then negative frequency must be real as well."
>Negative frequency resonant radiationhttps://arxiv.org/abs/1201.2689>Soliton-induced relativistic-scattering and amplificationhttps://arxiv.org/abs/1211.0256