Instructables

Does the point at which two light beams coincide appear to be more visible/greater intensity than the beams themselves?

Specifically, i'm interested to know if the coincident point of two laser beams would appear to have a greater brightness / intensity than the beams themselves. For example, I think I read somewhere that 15-25mW green laser diodes have a visible beam in med-low light conditions because they offset dust particles? So does this mean that where there are two light sources approaching from different angles that there will appear to be a greater amount of reflection from the dust particles?

Any information would be useful really, just to put my mind at ease...

Thanks :)


Burf3 years ago
Of course, light is just another form of electromagnetic radiation. Where two or more beams of EMR coincide is called the focal point. Its easy enough to prove, take a magnifying glass outdoors on a bright and focus the light passing through the glass onto the back of your hand, not only will you be able to see the intensity increase, you can feel it too.
Kiteman3 years ago
Yes.

Just like shining two torches on a spot makes it brighter than either torch on its own.

Yes, there will be more reflection, simple because you've got more beams. The spot they both focus on will still be brighter than a single spot from a single laser.