I once took an led string with naked leads, cut off the leds, and soldered on red laser diodes in their place. Then I could control it with an Arduino. I used it to make a laser harp!
You can use laser diodes just like you would a regular LED in an Arduino/rPi setup. They're basically the same thing electrically.
Be aware, using those standard laser diodes in public, especially for an event or show, is against the law because of the risk of blinding someone. If you want to do a laser light show or something, you need to use the sub 5 milliwatt kind they have at concerts and such, and you need a permit.
You can use laser diodes just like you would a regular LED in an Arduino/rPi setup. They're basically the same thing electrically. Be aware, using those standard laser diodes in public, especially for an event or show, is against the law because of the risk of blinding someone. If you want to do a laser light show or something, you need to use the sub 5 milliwatt kind they have at concerts and such, and you need a permit.