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Twin Blue Beams !

CurtisOliver

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Quite a lot of diodes have the thin beam as the fast axis. However the NUBM44 is an exception, as the wide part is the fast axis.
Ok, that's why it wasn't showing up. :)
 



Alaskan

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Where did you possibly find that info? I guess I will risk a quick edit and hope you see it. I mean the dye itself, the thin part of the laser diode chip itself is the fast axis, are you saying the thin part of the dye on this diode is the slow axis?
 
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CurtisOliver

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I did my own tests with the NUBM44 and found that the stripe just kept getting wider, and that the thin part was slower at increasing. Very odd indeed.

NUBM44 at close range [ --- ]and at far range [ ====== ]
 

Alaskan

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Thinking about this one for awhile.
 

CurtisOliver

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Normally the wider part of the beam is the slow axis. It is bit like squeezing the beam, fans out the beam more with the faster axis. Normally the thin part is the fast axis. I have just found that the useful output of the NUBM44 is the opposite for some weird reason.
 

Alaskan

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For all of my other multimode diodes, the stripe starts out in one polarity, lets call it horizontal, or vertical, if I hold the pointer that way, and then a horizontal oriented beam swaps to become a vertically oriented beam in the far distance. I don't have my NUBM44 laser diode pointer with me now to test this out with. Regardless of the physical orientation of the laser dye itself, it should still act the same way, just that the slow axis comes out the thin part, with this diode, correct? Does it act that way too or is that what you are saying, it doesn't?
 

CurtisOliver

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From what I have seen the NUBM44 works the opposite way which is the weird part. The axis that you would think to be slow is in fact the fast axis. All my other lasers act accordingly and either diverge how expected or match each other as they both diverge the same. I wonder if anyone else has noticed this.
 
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Accutronitis

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I have the fast axis aligned with the wide part of the heat sink (I'm a real nut when it comes to making things symmetrical) so the beam your seeing hitting the wall is the wide or fast axis, if you turn the laser on it's side the slow axis beam appears very thin, I kind of have my other laser setup the same way with the M462 diode fast axis aligned with the power button facing up so what you are seeing in the pictures is the wide part of the beam of both of my lasers and that is why both beams look so fat in the picture......

The glossy white really reflects a lot of power, I have a thin white plastic coat hanger that I can hit with the "Hammer" for 60 full second and nothing ! but it sure lights up the room (I'm wearing my new safety glasses of course) But if it had the least bit of color OR if I take a felt tip maker and put any color on it the "Hammer" is through it in seconds !

I also noticed when melting through dead clear colored lighters (Or African-American lighters if you prefer - Now that's not a racist joke, It's poking fun at racist people and the labels people put on other people) with the M462 that the color makes all the difference how fast it will melt through and oddly enough the clear blue lighter doesn't want to melt easily if at all, I don't know if it is something to do with the color of the laser is a close match with the color of the clear blue lighter or what ?
 
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Alaskan

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Look at the beam closely as it exits the pointer, does the smaller side remain the smaller side all the way out? How about 100 feet or more away?
 

Accutronitis

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Look at the beam closely as it exits the pointer, does the smaller side remain the smaller side all the way out? How about 100 feet or more away?
Let's put it this way, The beam is wide side to side on the wall from across the room when the lasers heat sink is sitting wide from side to side ? does that mean the fast axis or the slow axis is aligned with the heat sink ?
 
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Alaskan

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If I understand correctly, Curtis is telling me the physical structure of the dye for this diode dimensionally matches the propagation of the fast axis, so the wide side of the diode produces the wider higher divergence output. What you are indicating is that the output stays the same and does not cross over in the distance as other diodes do, which matches his observation.
 

Accutronitis

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If I understand correctly, Curtis is telling me the physical structure of the dye for this diode dimensionally matches the propagation of the fast axis, so the wide side of the diode produces the wider higher divergence output. What you are indicating is that the output stays the same and does not cross over in the distance as other diodes do, which matches his observation.
That's interesting and I just learned something new so it's going to be a good day !
 

CurtisOliver

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Yes this is correct. To elaborate further. Accutronitis, do you see A or B at a distance?
Just imagine the characters as the overall rectangle beam profile.
A. -- to =====
B. -- to |||||

x = > y = ^

A) x = Fast axis, y = slow axis
B) x = Slow axis, y = fast axis

Most diodes you come across are B. Where the NUBM44 is A.
 

Accutronitis

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A ===== when using a G-2 lens and more of a ==== when using a 3-lens.....
 
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CurtisOliver

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Thanks Accutronitis, you've confirmed my findings. :) What would usually be the slow axis is actually behaving as the fast axis.
 

Accutronitis

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I think I need to clarify something....

Here is how the diode is mounted in the laser with the red line being side to side.....





Next is the beam with no lens on the wall and it is huge but the beam is much wider top to bottom........







next is the beam using a 3-lens unfocused on the wall and is wider top to bottom but much smaller.....







Now next is the beam on the wall focused BUT side to side the beam is not compressed as much as it is top to bottom SO NOW the beam is wider side to side......

Really it's not that close to the same width but I think you get what I mean ? The top to bottom is "squeezed" down much more than side to side so when focused the beam becomes wider side to side......








Does this make sense ???
 
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