It gets even better if the guard beam is a different frequency than the power delivery beam as the glitter could be transparent enough to the guard beam, but no

It gets even better if the guard beam is a different frequency than the power delivery beam as the glitter could be transparent enough to the guard beam, but not transparent to the main beam. They also don’t seem to be addressing the problem of the solar panel getting dirty/scratched and becoming more reflective. This is a much harder problem to solve correctly than a simple guard beam. Disclaimer: I’m involved with a company making high power versions of this tech for industrial/military uses.