The Laser's only function is to detect objects if it is paired with a Laser Detector. The Laser emits a thin, red beam which does not hurt the player if touched. The beam being emitted can be blocked by a player or any item, including wood.
It is more effective to use a Signal Inverter when using a Laser with a Laser Detector as that means there will be an output when the beam is being blocked by an object. This can be effective in a scanning machine as there will be a signal telling the player when there is an object where the Laser is.