[Breaking Taps] has a nice pulsed fiber laser and decided to try it to micromachine with silicon. You can see the results in the video below. Silicon absorbs the IR of the laser well, although the physical properties of silicon leave something to be desired. He also is still refining the process for steel, copper, and brass which might be a bit more practical.
The laser has very short duration pulses, but the pulses have a great deal of energy. This was experimental so some of the tests didn’t work very well, but some — like the gears — look great.
This probably isn’t going to work with your $200 Chinese laser engraver. But if you do have the right kind of laser (his is a generic one that runs about $4000-$6000), the tips about focal length and timing will probably save you some experimenting on your own.
We have to admit we were a bit jealous. Not only does he have access to a fairly nice laser, but he also has access to a scanning electron microscope which is of better quality than the ones we used to use and we don’t even have access to those anymore. You can see a lot of analysis of the parts carried out under the SEM in the video.