Here's what you do ~ to make it better ~ and able to cut through aluminum foil or set fires at a distance ~ index the wave generator about 45 degrees to the direction of the vacuum tube. Actually, forget the vacuum part ~ fill it with CO2 (or any other gas that can generate light when induced to do so with a radio wave.
Set up your mirrors at both ends of the tube. Leave a small hole for the emission of the coherent wave form.
And these guys got patents on this?
“Coherent...so it can talk?”