635nm vs 650 nm laser

[firelaser]

i already have a 500mw blue and 100mw green laser but no sort of red laser, i al looking at a 250mw 650nm red laser and a and a 200mw 635nm red laser, and i was wondering what the difference of the two would be, such as performance, brightness, divergence, beam visibility and witch can be seen on a target further away,, thanks laser experts!

 

[InfinitusEquitas]

The 650nm will have much better divergence, and beam quality.

The 638nm will appear to be much, much brighter, but with bad divergence, and a dirty looking dot.

There are some great threads on this by Ash, Lazeerer, Smeervost and others...

 

[firelaser]

ok so the 635 nm will be simular in beam quality and divergence to my blue laser then.. right?

 

[InfinitusEquitas]

No, 635nm will be even worse than 445nm. It's about twice as bad in terms of dot and beam, but still a whole lot brighter than a 660nm laser.

In reality you're really talking about ~640nm laser vs ~660nm laser, and in terms of visibility that 20nm difference is very apparent IMO.

Of course with fog either will produce a nice beam.

 

[RA_pierce]

ok so the 635 nm will be simular in beam quality and divergence to my blue laser then.. right?

That depends on the diode and lens you use.

I really like the single mode ML520G54 638nm diodes. Their beam shape is very similar to the LOC 655nm diodes like the LPC-826 & -815. The 638nm beam is only slightly more elliptical than the 655nm which is very circular.
This diode is only rated for 110mW but at 80mW it is about the same brightness as 250mW 655nm if not brighter.

Here is a recent build of mine with the ML520G54 diode with a comparison of the 638 80mW vs 655 250mW:
http://laserpointerforums.com/f50/638nm-80mw-single-mode-pen-beam-star-photos-78588.html#post1130515

The higher power 638nm diodes use a larger emitter for more light output but the beam will resemble the high power 445nm diodes only with a larger divergence angle. The beam divergence, that is, how big the beam spreads over a distance is also affected by the lens you are using. Some people use lenses that cut off some of the beam for a better shape but less power. Others will prefer the higher transmission lenses and a more divergent laser.

Note that in the pictures of the single mode diodes' dots, the bar through the dot is exaggerated because of the 650-G-1 lens. An acrylic or 3 element glass Aixiz lens will hide more of the bar but also passes less light. For comparison, see the multimode diode here: http://laserpointerforums.com/f50/here-300mw-635nm-mitsubishi-66942-27.html#post1041848

 

[Blord]

The 638nm diodes have also different beam quality and divergence. The bad beam spec that InfinitusEquitas is talking about are the Mitsubishi 300mW and 500mW diodes. They have very bad beam specs and the dots looks like a long bar.
Other 638nm diodes like the Mitsubishi 110mW single mode, Sanyo 40mW or the Opnext HL63133DG are more like the 660nm diodes.

http://laserpointerforums.com/f52/e...m-hl63133dg-single-transverse-mode-79033.html
left: 206mW Mitsubishi 300mW diode
middle: 210mW Opnext 170mW diode, the dot is better than the single mode Mitsubishi 110mW diode.
right: 60mW Sanyo 40mW diode, look at the wings on both sides of the dot.

 

[Smeerworst]

http://laserpointerforums.com/f48/laser-beam-comparison-78140.html

Control shot

635nm Mit$u 300mW diode and 500mW diode doing.

Both using same lenses.
>500mW left
>1W right.

445nm M140 >2W

 

[firelaser]

deleted wrong reply

 

[firelaser]

OH ok so this one would most likely ook like the left most dot? LZCB - CYBER 638nm 300mW Bright Orangish Red Laser Pointer

 

[firelaser]

ok now the link should work... LZCB - CYBER 638nm 300mW Bright Orangish Red Laser Pointer

 

[Smeerworst]

OH ok so this one would most likely ook like the left most dot? LZCB - CYBER 638nm 300mW Bright Orangish Red Laser Pointer

If you would like to call that a dot, then yes it would look similar to the ''dot'' line on the left.

Did you read the fineprint under that link you posted ?

*Due to the fast axis divergence of 638nm laser diode. The dot of this laser will be focused as slightly line shape rather than perfect dot. A small shadow appeared next to the dot is normal phenomenon and will not affect the using.

 

[Lethere Belight]

ok now the link should work... LZCB - CYBER 638nm 300mW Bright Orangish Red Laser Pointer

I got one of those. When I got it I thought something was wrong. UGLY "dot".
After some research I learned thats what they do. I also then saw this in the advertisment:
*Due to the fast axis divergence of 638nm laser diode. The dot of this laser will be focused as slightly line shape rather than perfect dot. A small shadow appeared next to the dot is normal phenomenon and will not affect the using

If I would have known that never would have got it.
But it does have a nice beam.
Sorry Smeer, vdidn;t see your post. You said the same.

 

[firelaser]

yes i have the same concern lol ,, so is that one o dark orange in appearance or does it not really look different than a regular red ?

 

[Lethere Belight]

I don't know if I would even call it "orange" but the BEAM is more noticeable (at night when I use it)
Do you want a BEAM or a DOT?
For the dot a 650.

 

[firelaser]

well i guess i would use it for pointing at stars and inpressing people with its brightness... and i have a 100mw green witch is good for the dot..

 

[Atomicrox]

The color is noticeably different if you see both side by side - I like 638nm better. If you look at the 638nm alone it will look red.