A typical optical transfection protocol is as follows:
1) Build an optical tweezers system with a high NA objective
2) Culture cells to 50-60% confluency
3) Expose cells to at least 10 µg/ml of plasmid DNA
4) Dose the plasma membrane of each cell with 10-40 ms of focussed laser, at a power of <100 mW at focus
5) Observe transient transfection 24-96h later
6) Add selective medium if the generation of stable colonies is desired