300mw 635-638nm laser visibility

[Me wants laser]

Hey guys, I'm interested in buying an orange-red laser that is 300mw and I want to know how visible it is at that power. Is the beam visible at least at night, and how visible is it? Is it as visible as the beam of a 50mw green laser at least?
Thank you!

 

[Deleted member 42751]

Hello!
A 300mW 638nm laser will have a beam approximately as bright as a 50mW 532, but much more so outside. This is because the beam of a 638 is less bright relative to its dot; a 638nm laser's beam can be drowned out by the dot. Once you go outside, though, and the dot is far away, the beam can be seen much more easily. :beer:

 

[Me wants laser]

Hello!
A 300mW 638nm laser will have a beam approximately as bright as a 50mW 532, but much more so outside. This is because the beam of a 638 is less bright relative to its dot; a 638nm laser's beam can be drowned out by the dot. Once you go outside, though, and the dot is far away, the beam can be seen much more easily. :beer:

Okay, thank you!

 

[BowtieGuy]

Your 300mW beam we be plenty visible at night; I have three or four single mode 638nm lasers all less than 300mW (234 - 260mW), and they are easily seen in the dark.
Two of mine are shown in the links in my sig, most pics were taken with light fog in a semi-lit room.

 

[Me wants laser]

Your 300mW beam we be plenty visible at night; I have three or four single mode 638nm lasers all less than 300mW (234 - 260mW), and they are easily seen in the dark.
Two of mine are shown in the links in my sig, most pics were taken with light fog in a semi-lit room.

Yeah? Thanks, you have a lot of lasers, that's cool haha.

 

[Deleted member 46822]

Hello!
A 300mW 638nm laser will have a beam approximately as bright as a 50mW 532, but much more so outside. This is because the beam of a 638 is less bright relative to its dot; a 638nm laser's beam can be drowned out by the dot. Once you go outside, though, and the dot is far away, the beam can be seen much more easily. :beer:

I don't yet have a 638, but this seems to explain alot and just realized why when members post beam pic's this must be why the dot splash kinda drowns out the beam.
These are a single mode diode but with a bad divergence?

 

[Gabe]

I don't yet have a 638, but this seems to explain alot and just realized why when members post beam pic's this must be why the dot splash kinda drowns out the beam.
These are a single mode diode but with a bad divergence?

The lower powered 638s like the one I have actually have incredibly low divergence and a really tight beam! It's only when you get up to the 500+mW diodes where the beam becomes that nasty line shaped dot with the terrible long axis divergence.

 

[Deleted member 46822]

The lower powered 638s like the one I have actually have incredibly low divergence and a really tight beam! It's only when you get up to the 500+mW diodes where the beam becomes that nasty line shaped dot with the terrible long axis divergence.

I was thinking a bad wider divergent beam for lack of beam brightness. As far as the brighter dot relation, i'm not at all gifted in light physic's but why are the first gun laser's red, better visiblity for all conditions of shooting or just way cheaper and simpler to produce?

 

[CurtisOliver]

There are a few reasons I can think of.
1) Red's are better for your night vision, whereas green can disrupt it.
2) Red's are cheaper.
3) Green's are more temperature sensitive.
3) Depending on application, eg military use. They don't want high visibility in order for the guns location to be kept secure. This is why they use IR nowadays along with IR goggles.

But there are also benefits of using green over red. It just depends on what you use the gun for.

 

[Gabe]

Yeah I agree, in the earlier years reds were the cheapest by far, and they still had a clear visible dot. Now that green lasers have become cheap they're more popular because they're the brightest per mW, and that's important when abiding by the <mW law

 

[CurtisOliver]

Yep, laws preventing anything over 5mW have made greens the best alternative for most. Just not the stealthiest wavelength