OK, I am down...
How much and where?
THAT is the question.... I see many videos but WHO is selling a
working unit and I still want to know what the post surface is, post
laser cleaning. I bet ya you still have to blast the surface.
Cooking oxides can only leave debris/coating , yes?
I am in the laser business and can offer some insight. The laser in the video looks to be a focused, scanning variety. I'd guess 1064nm(color of light) @ 20Watt(output energy) or more. Probably a fiber or YAG type(how the beam is generated) Good brand name lasers such as these are tens of thousands of dollars in cost. They typically have a small field of view and are used for high precision processing and marking applications. They are not a practical solution for large scale rust removal such as would be done with a sand blaster.
The laser beam is directed through a lens which focuses it down to a spot like the old sunlight through a maginfying glass experiment only much hotter if desired. Hot enough to cause a plasma reaction on the surface of steel for example. The beam is typically passed over two rotating mirrors before the focus lens. These mirrors move the beam in X & Y axis across the face of the lens, which causes the focused beam to move in X & Y axis on the surface being lased. The beam can be moved at very high speeds to 6000mm/sec. The energy levels & speed of the beam's movement, and path are all programmable to achieve the desired result. Such as lightly lasing a white background on an aluminum casting, then agressively lasing(burning) a black QR code onto it which contains data of some type to be machine readable. The black code on white background gives a high contrast appearance similar to that of a white label with black ink.
The post surface condition varies depending on the material and type of surface lasing that is performed. Mild steel will instantly oxidize(rust) when agressive marks/engraving occur, however milder high speed lasing can act to shine up the surface by removing surface impurities. Steel parts that are laser marked typically fare better in automotive salt spray(extended life rust) testing where the mark is made.
Vacuum extraction is typically used to pull debris from the area so it does not affect the process or remain on the surface. When cleaning metals, the debris is usually "cooked" into such tiny partices they pretty much dissappear, especially with vacuum extraction.