A laser beam hitting a column of liquid controls the droplet pinch-off at the bottom of the stream.

In the past, I added some claims on that this might be possible with laser prism scanning.

Remember the post (printing with droplets) with obscure claims like I claim that the Hexastorm is used to force the break up of droplets in a continuous inkjet head using heating.

Now, there is a good write up on laser induced breakup on https://physics.aps.org/articles/v14/174 for those who are interested.