I've never seen this before. It's a cool concept but I don't see how it would work practically.
My guess on the working principle:
Photons are guided just like in a wave guide due to higher refractive index of the particle beam compared to the vacuum.
The particles are trapped similar to optical tweezers due to gradient force.
But how do those two combine? For it to work, I would expect higher density toward beam center. Kind of like a graded index fiber. That way we have the wave guiding and the field gradient.
But for the wave guiding, I would assume you need a certain minimum particle density, which would require a ton of particles if you're talking long distances. Scattering leads to losses but also heats up the particles, meaning the gradient forces and therefore the photon beam need to be stronger as well. However, this in turn also increases the scattering.
So there are significant losses and the range is limited.