Fast acting gate for laser?

Got a project where I'd like to turn a laser on and off somewhat quickly, on the order of turning the laser on for as little as 20ms to upwards of 1s.

with the laser controlled by a mosfet; it appears the laser takes much longer to turn off and on that trying to turn it on for most intervals in this range results in no output.

so I'm thinking I may just turn the laser on, put a bigger heatsink on it, and find a fast way to block and unblock the beam. Not a burning laser so that shouldn't be an issue.

any ideas? Stepper motor or servo to whip a cover in and out of place?

Just thinking out load but maybe an LCD screen?

20ms is only 50Hz. Any mosfet can switch much much more quickly than that. Your problem lies elsewhere, probably in the circuitry for the laser module?

I agree - the laser module probably contains a capacitor, which is powering the laser for some time after you remove power to it. Preferably, tap into the module's electronics rather than just turning the power on/off.