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Re:How I Got My Laser Eye Injury by hinkley on Thursday August 01, 2024 @02:01PM (#41131771)
I know one of the reasons we wanted pico-second and shorter pulsed lasers is that they can cut material with little to no damage of the neighboring material. There was a demo that I read about when this was all brand spanking new research, where they claimed that a laser scalpel causes no heat damage to tissue outside of a cell’s breadth from the contact point.
Re:How I Got My Laser Eye Injury by cyberax on Thursday August 01, 2024 @03:50PM (#41132859)
That's how LASIC and PRK work, after all!
Re:How I Got My Laser Eye Injury by justinclift on Thursday August 01, 2024 @09:53PM (#41135469)
Re:How I Got My Laser Eye Injury by eaglefield on Friday August 02, 2024 @07:23AM (#41137894)
It's related, but as i recall the reason that short pulses cut better has to do with heat transfer. Most heat transfer in metal is due to the vibration in the electrons, being much lighter than the atomic lattice they move in. Very short pulses, means that the heating in the beam path happens faster, than the electrons can transfer it out to the rest of the metal. In long pulses once the metal is vaporised, a lot of the surrounding material has melted. This molten metal cools into jagged structures and that leaves the edge weird. All this doesn't happen if the pulse is short enough. It vaporises metal before the surrounding structure has a chance to heat up.

Here's a figure showing the quite stark difference. https://www.researchgate.net/figure/SEM-image-of-the-substra...

Re:How I Got My Laser Eye Injury by justinclift on Friday August 02, 2024 @07:42AM (#41138001)
Awesome, those photos do illustrate the difference really well.

Thanks heaps. :)

Re:How I Got My Laser Eye Injury by eaglefield on Friday August 02, 2024 @07:09AM (#41137828)
Here's a figure comparing the hole left in a metal surface with normal and femto-second pulses. The difference is quite stark.

https://www.researchgate.net/figure/SEM-image-of-the-substra...