Comment by dotancohen
Comment by dotancohen 19 hours ago
A 45 watt light bulb spreads the energy in all directions - at 1 meter away that's about 3 watts in every square meter or roughly 0.000003 watts per square millimeter. The laser is putting 45 watts into that same square millimeter at the same distance.
Of course the laser is tightly focused. That's pretty much one of the defining properties of laser devices. How else do you think the laser is heating the microprocessors in the video?
They will be using a beam spreader to conform to the size of the targeted IC, which is usually on the order of 5x5 mm and up. For smaller parts they will be reducing the power.
They shouldn't be focusing it to a point under any conditions. Whether it's as safe as it could be is a different question, of course. For instance, you'd like to think that the act of configuring it for a smaller beam footprint would reduce the power at the same time, as opposed to requiring a separate adjustment that might be overlooked by the operator. Would have been nice if the video had addressed that and other safety considerations, for sure.
A lot depends on the exact wavelength. 1400 nm and longer is much less worrisome than near-visible IR.