How to make a bouncing laser beam?

I want to make a puzzle game with a laser mechanic similar to the one found in The Talos Principle.
Here is what I want, exactly:
1) Item that produces laser, player should be able to move this around.
2) Mirror or surface that reflects the laser
3) Collider that receives the laser and puts out a signal (or switches a boolean in my code to "true" so I can open a door or something.)

How would I go about doing this?