Never did brown glass, but I would not be surprised if the results for white glass apply:
- Laser engraving glass - tried several methods, here are the results
- Engraving glass surface by laser 1600mw
TL;DR: Lasering glass works (white glass needs coating), the result is not as fine as etching or sandblasting, but not too bad after all.
It would be interesting to see if brown glass even works without coating…