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ArcticMyst Security by Avery

Lasers and Mirros

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Cam anyone explain for me technically why my lasers beam appears brighter when reflected off a mirror compared to the beam hitting said mirror. Also beam diameter increases a bit which I assume is due to scattering off a surface with microscopic porousity?

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Rayleigh scattering, the phenomena responsible for visible beams, preferentially favors viewers near the axis of the beam onlooking from the target as opposed to onlooking from the source. The increased beam size is due to the divergence and added beam distance, the increased beam cross section helps the beam seem brighter since more receptors in the eye are influenced even though the intensity is proportionally lower.


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Sig seems always on the spot
with good info !!
And his grammar is correct.
HMike
 
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Okay makes perfect sense but I just had a debate on another thread about beam width and its relation to visibility assuming equal outputs. I said thicker beams should be more visible to an extent (for the same reason you explain though i referred to the increase in particles the beam would encounter rather then the result of more stimulation of rod/cone receptors) and was seemingly proven wrong with a photo. But you seem to be validating my view. Can you clear up this confusion for me please it'd be greatly appreciated!

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I said rods and cones cuz I dont recall which are responsible for color

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Intensity is lowered with beam width for a given power, so how visible the beam is becomes reliant on contrast with environment and the density of the scattering material in the air. I.e. It becomes hard to objectively quantify, much like any perception dependant stimuli.


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True way too many variables for objective numbers in a subject such a visibility which is intrinsically subjective. Thanks sig for the replies great info just what itbwas looking for. Thanks!

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Joined
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Sig seems always on the spot
with good info !!
And his grammar is correct.
HMike

Lol good grammar is a plus. My phone is awful for typing grammatically correct posts guess iPhones are better eh.. edit.. although he did forget to put "and" in there as its required when only two points are being made. But I hated English in school so what do I kno lol. Edit again.. im wrong the grammar is right. See told you grammar sucks!

Thanks again tho sig much appreciated grammatically correct or not.

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Always glad to help!

Idk about android, but the autocorrect in iOS is adaptive and learns the user's habits and adjusts itself to the user the more it is used. It helps a lot, but I also proofread my posts and I tend to talk similarly to how I type, as far as sentence structure goes.


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Same here as far as how I word my typed sentences but my phone doesnt learn for shit. And im out of hard drive space. Galaxy pos.

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Intensity is lowered with beam width for a given power, so how visible the beam is becomes reliant on contrast with environment and the density of the scattering material in the air. I.e. It becomes hard to objectively quantify, much like any perception dependant stimuli.


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This is pretty much what I said in the other thread - and proved with an image, but the op is a different question. Beams coming towards you appear brighter than ones going away from you because the light scatters towards your eyes easier when it's coming towards (rather than going away) from the observer.

Marco Polo posted a thread observing the same thing in general a few months back.

OP if you still don't trust me that thinner beams look brighter where other variables remain the same (power, ambient brightness etc) then buy a handful of 532 pen lasers, lpm them all, sort them by power and then pick a bunch that have roughly the same power, switch them on and observe that indeed, the ones with the thinnest beams are brighter.
 
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No no I believe you trencheel im sorry i dont mean to imply one or the other view is wrong im just slowly putting pieces together. Tbh im quite young and little in the way of formal education so these topics are at the edge of my current comprehension of these matters for the time being. I got diff answers cuz the OPs were different questions. I thought there was an anomaly but the way both of you explained things adds up perfectly. Appreciate you both for helping me out. I really need to invest n a few more textbooks.

Edit. Thanks for having patience with me too guys. I dropped out of school after fifth grade and taught myself since then besides a few classes at community college around where I live so I really do appreciate the positive and quite helpful feedback

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Cam anyone explain for me technically why my lasers beam appears brighter when reflected off a mirror compared to the beam hitting said mirror.

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It is brighter because more photons are entering your eye when the beam is reflected than when these photons are traveling away from you. It would be the same if you were to shine this laser directly into your eyes versus the beam traveling away from you.
 
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The effect is caused by Rayleigh scattering it's been explained and I'm familiar with the phenomenon. Thanks for your input though

Edit. Thank you really man. You explained it simply when viewing from the source only scattered photons are detected but if the beam is arms towards you photons from the source also enter your eyes thus making it appear brighter.
 
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Use first surface mirrors if possible as reflection is around 98% and standard mirror 70/80%
 




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