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Visible Blue?

lamborgini8

lamborgini8

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I know you can see a green beam at power levels as low as 5mw but what power level is needed to see a blue beam? Even the 5mW blue lasers are like $800, would be gutted if I got one and found out you cant see the beam.
 





andy_con

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blue isnt the most visible laser.

its kinda the same as red visibility wise
 
lamborgini8

lamborgini8

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andy_con said:
blue isnt the most visible laser.

its kinda the same as red visibility wise
Click to expand...

I see... what power would I need to see a blue beam then? Or even just see it through smoke.
 
andy_con

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well like a red a small amount of smoke will enable you to see the blue beam
 
C

Cxrazy

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basing my knowledge on the assupmtion that red and blue have about the same visibility, it'd be about 150mw-200mw to see a blue beam in the dark.

Wrong? :-?
 
RA_pierce

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Here's a chart showing the sensitivity of the human eye to specific wavelengths:
All the hand held blues I've seen are 473nm which is somewhere in the middle of the blue section on the graph. Its visibility should be similar to that of a 635nm red. I have no problem seeing a 5mW red beam at night (at least when looking down the beam to the aperture) but the red I have is probably around 640nm because when compared to a 650nm red it's much brighter and slightly orange-ish. Its labeled as "650nm +/-10" which leaves room for about a 10nm difference either way.

I would think 15-20mW of blue would be about as bright as a 5mW green. The beam may even be brighter at night than a 5mW green because the atmosphere scatters longer wavelengths more.

Correct me if I'm wrong...


eye_20sensibility.jpg
 
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pseudonomen137

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blue is particularly visible at night when scotopic vision takes over. The photopic luminousity spectrum peaks ~555nm, but scotopic is closer to blue. At night, just going out without fog or anything, I can see the beam of a 15mW 473nm blue without too much trouble. Heck, I can even see it in a lit room at the right angle, although that's a bit of a long shot.

No question that blue is less visible than green, but whereas it take MUCH more red to match a green, blue doesn't seem to lag too far behind.
 
C

Cxrazy

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Then I was wrong. :)

haha, I wish I could afford a blue... :( Maybe I'll make a bluray or summat.
 
Cyparagon

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The single line models usually output 488nM. The multiline models usually output 456 to 514nm.

RA_pierce said:
I would think 15-20mW of blue would be about as bright as a 5mW green. The beam may even be brighter at night than a 5mW green because the atmosphere scatters longer wavelengths more.

Correct me if I'm wrong...
Click to expand...

You mean shorter wavelengths. 473<660. I would theorize 20mW at 473nM is brighter than 5mW at 532nM as well. Partly because of the atmospheric scattering, but more so because of scotopic vision (night vision, peak at 506nM)
 
RA_pierce

RA_pierce

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Cyparagon said:
You mean shorter wavelengths. 473<660. I would theorize 20mW at 473nM is brighter than 5mW at 532nM as well. Partly because of the atmospheric scattering, but more so because of scotopic vision (night vision, peak at 506nM)
Click to expand...

Haha yeah, I meant shorter.
 
styropyro

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Cxrazy said:
Then I was wrong. :)

haha, I wish I could afford a blue... :( Maybe I'll make a bluray or summat.
Click to expand...
I have a Blu-ray that is probably something like 5mW, and the beam is way brighter than a red, at night you don't even have to look hard to see the beam, it is easily brighter than my DIY red (Well over 100mW). I would start with a Blu-ray first before getting a true blue laser, because almost everything the blu-ray dot hits floureces blue, and you can easily build one for under $40 (and you can find all of the electrical parts at Radioshack). Here's a picture of a blu-ray flourecing blue off of a white box.
lasers 002.jpg
 
Gazoo

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Wow Styro, your eyes must be sensitive to ultraviolet. At night my reds are like 100 times brighter than my blu-ray...interesting.
 
MarioMaster

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RA_pierce said:
Anyone have an Argon-Ion laser? What wavelength(s) do they lase?
Click to expand...

Taken from Wikipedia: Argon lasers emit at several wavelengths through the visible and ultraviolet spectrum: 351 nm, 454.6 nm, 457.9 nm, 465.8 nm, 476.5 nm, 488.0 nm, 496.5 nm, 501.7 nm, 514.5 nm, 528.7 nm.

and i do have one, it's just not 100% working yet :(
 
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