JBTexas
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- Jun 5, 2011
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First of all, I DID try to google this, and I DID try a search on the forum.
Okay... I've wondered about this off and on for a long time. I first noticed it with my ~ 5mw red HeNe back in the late '70s.
Put a focused laser spot on say, a white wall (glossy paint) - it doesn't seem to matter what TYPE of laser or COLOR, or for that matter, output. I can see this with a 5mw green laserpointer.
... and observe the diffuse "backwash" or "splash" of light on, say, the top of a nearby bookshelf or most other objects.
Objects illuminated by the "splash" seem to "shimmer". As if they are coated with a thin layer of vaseline mixed with "sparkly stuff".
Countless tiny "sparkles"... if you remain perfectly still, these countless tiny "spots" seem more-or-less stable... but move your head, and the sparkles seem to "move"... they kind of follow your head movement / eye movement.
Countless tiny interference patterns? The light in the splash can't be spatially coherent anymore, GENERALLY, though it is still chromatically coherent. Zillions of little coherent bits, from micro-reflections, interfering w/ each other, going in and out of phase? Or what?
Okay... I've wondered about this off and on for a long time. I first noticed it with my ~ 5mw red HeNe back in the late '70s.
Put a focused laser spot on say, a white wall (glossy paint) - it doesn't seem to matter what TYPE of laser or COLOR, or for that matter, output. I can see this with a 5mw green laserpointer.
... and observe the diffuse "backwash" or "splash" of light on, say, the top of a nearby bookshelf or most other objects.
Objects illuminated by the "splash" seem to "shimmer". As if they are coated with a thin layer of vaseline mixed with "sparkly stuff".
Countless tiny "sparkles"... if you remain perfectly still, these countless tiny "spots" seem more-or-less stable... but move your head, and the sparkles seem to "move"... they kind of follow your head movement / eye movement.
Countless tiny interference patterns? The light in the splash can't be spatially coherent anymore, GENERALLY, though it is still chromatically coherent. Zillions of little coherent bits, from micro-reflections, interfering w/ each other, going in and out of phase? Or what?
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