Tenth of a mm? Seems nothing is impossible apart from getting the edge sharp in the first place. You could give yourself a nasty bruise with an edge that sharp...
Impressive work, no doubt about it, but I get the feeling that a good degree of 'artistic licence' has been applied to the wording of the piece
"On the sharp edge" and "letters a tenth of a millimeter high" simply doesn't correlate. Try putting anything a tenth a of a millimeter wide directly onto a properly sharpened edge ... and all you'll end up with is some bits that are about 0.05mm wide
"Onto the bevel" or "On the edge of the thickness of the blade" I would believe, but not 0.1mm on the edge itself. As Demographic says, if you can put something 0.1mm onto the edge, you've got an 'edge' that could give you a nasty bruise