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Laser beam brightness vs wavelength: Seeking personal experiences

Philipnzw

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May 19, 2019
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Was about to post something similar but thankfully i stumbled upon this post first.

The laser beam comparison tool says that watt for watt, the 650 red should be 24x brighter than 405 violet.
But in my case, they look about the same in terms of brightness. (From comparing my 200mW red and 200mW violet. )

It could be a genetics thing or just individual differences. My brother says that he can see 405 violet's dot somewhat clearly whereas in my case its a complete blur.
 



Spoomples

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I've been thinking of adding a toggleable 'fudge factor' to the calculator to compensate for things like that. I just need to get enough data to make a reasonable adjustment curve, there wouldn't be much point to it if it makes it even more inaccurate.
 

Alaskan

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I can't see the dot clearly for 405 nm (a complete blur), even 650 nm red is a bit out of focus for me now.
 

CurtisOliver

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405nm is hard to focus on for me too. 650nm is sharp however.
 

RedCowboy

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In my own testing of spot visibility during daylight hours outdoors I find my 250mw 638nm single mode makes a visible spot even in bright sunlight nearby and far field upon shaded surfaces, yes the 520nm 1w also shows up well but in this case beam quality compensates for a less visible wavelength and less output however 650nm is not nearly as visible as 637-638nm and as for beam visibility beam quality also comes into play so beyond wavelength and output beam quality is also a factor.

Sharp GH0631IA2GC
 
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Spoomples

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My current thoughts about corrections for lower powers: Its probably not necessary for dots, as the are pretty bright even at low powers. But for low power beams in clean air, assume they are seen with mesopic vision. Dark rooms are well into the mesopic range after all, and you won't have much luck viewing the beams in anything brighter (which means the beams themselves are very dim). The tricky parts will be figuring out the right coffecients for the mesopic equation for a given wavelength and power.
 




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