I know lasers are able to retrieve data (HDD, laser distance meters, optic telescopes etc.) but how does one do it? Let’s take distance meter as an example, let’s say I want to measure how far away I am from a wall. No wall is 100% smooth, so when I point a laser beam into it it should bounce off in some unkown place due to rigidness of the wall. I mean as far as I am concerned laser beam should bounce off of the wall and go back to the detector, and it does its magic and it somehow knows how long did the light traveled. But rigidness of the wall should make it bounce somwhere (angle of incidence equal to the angle of reflection).
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The only thing that would actually completely reflect the light off into a different direction is going to be a mirror, and even those aren’t perfect.
So the tl;dr is that basically, no material is going to do what you think is happening. At least *some* of the light will get bounced back directly to where it came from so it hits the detector and thats how we measure distances.
As for how they do that, we send a really quick pulse of light and then measure how long it took for the light to be seen by the detector.
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