blue laser question

[george2524]

Hi all,
New to the forum and lasers in general. I recently purchased red, green and blue laser pointers from fleebay. All were stated to be burners, and they indeed do. The blue lights matches in less than a second. The beam it puts out is nearly invisible. Yesterday before work it was quite foggy so I took them out to check out their beams. Green and red where nice and bright but the blue, even in the fog, was so dim I could barely see it. The blue is the most powerful burner of the three.

My question, is this typical of the blues. I intend to build a scanning projector soon. In the opinion of the members here which blue diode gives the brightest most saturated beam. Should I use two diodes and converge them into one beam? I would like to keep the costs down as much as possible. I know that is nearly impossible lol.

 

[EllyEnthusiastic]

I can't answer your projector question, but I can confirm that blue/purple diodes usually burn well and are less visible than other diodes of the same power. It has to do with the eye's low sensitivity to blue light, and the fact that many purple beams are just on the edge of the visible spectrum. They're very close to being ultraviolet!

 

[RedCowboy]

Elly your avatar is hilarious. I smile every time I see it.

 

[Isaac Clarke]

i think your are refering to 405nm or 445?

 

[Pi R Squared]

I think the blue is not blue, but is violet 405nm, it is barely visible, blue is very visible.

Alan

 

[Bionic-Badger]

If you want brightest blue, you'll want those 462nm laser diodes. The only problem is that they don't have the best beam-shapes. For a single-mode blue, i.e., one that produces a nice dot, you'll probably want the ~445nm blues such as the PLP450.

Those 445nm lasers produce a deep blue, but it is definitely blue, not violet. It'll be pretty saturated, but also not extremely bright because it's just not a very bright wavelength for our eyes. The 462nm lasers move more towards cyan so they're quite a bit brighter. How "blue" it appears compared to 445nm is subjective, but probably only when compared against each other. It's kind of like the difference between 650nm and 635nm. People describe 635nm as "orange-ish" but it's not a huge difference aside from being quite a bit brighter per mW compared to 650nm.

 

[george2524]

Thanks for all of the great responses. Bionic-Badger thank you for the diode tips.

 

[EllyEnthusiastic]

Elly your avatar is hilarious. I smile every time I see it.

PSA: always wear safety glasses, and also don't bungle around with dark magic.