Question

Why can we see laser if they move in one direction?

Answer 1

Answer:

It will bounce off at the same angle it hit. If you shine a laser on a mirror, you can only see the light if you are in the direction it bounces ..

If this happens, the atom will go back to its ground energy level and emit a photon (photon 2) in the same direction as the photon number 1. This is called stimulated emission. ... Some of those photons will eventually hit your eyes, and this is why you might see the laser.