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First "builds"

tony23

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Just finished my second assembly. Not really sure i can call it an "assembly" or "build", since most of the work was done by others - I just soldered the module into the host and tightened a screw :)

Either way, here they are:
lasers.jpg
Smaller one is a PLTB450B 1.6w 450nm. I did that one first before messing with the big one. That's a NUBM44. Both ordered from DTR's Laser Shop and both hosts from @Lifetime17 - (thank you for the guidance, too!)

I don't know how to safely take pictures of them in action - I'm concerned they might blow out my phone camera without some sort of protection for the lens.

Either one can light a match pretty easily. I got a couple good lessons in how much power these things have though, when I was trying to focus the 1.6W one on a dining room chair and started noticing some smoke forming! The big one did the same to the deck rail when I was focusing it too (not unexpectedly that time, but faster than expected). I think I need to figure out better focusing targets.

I'm wondering about the beam spread, though. I can get it pretty tight up fairly close. As the distance increases it starts getting more rectangular. If I'm understanding right, it's because these are actually a number of diodes set in a line to get the intensity? What I'm NOT understanding is how those lasers you see on the videos popping balloons and lighting matches across a room keep such a tight beam.

I guess next step for me will be building my own driver. Need to get more tools before I can get into any sort of host fabrication...
 



Anthony P

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The rectangular shape is the normal propagation of a single diode emitter. Research fast and slow axis.
 

tony23

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The rectangular shape is the normal propagation of a single diode emitter. Research fast and slow axis.
It looks like it's made up of a line of squares, which is why I thought what I did. Thanks for pointing that out, learned something new.

Still leaves me with the question about how they do it in all those videos. They still look like a spot clear across a room. From what I read, you CAN do something about it with various lenses but it doesn't seem like something you could do in a single portable construct.
Are the wires you soldered with 26Awg or 30Awg?
Which ones are usually used?
Sorry, no idea. I didn't size them. They were whatever leads came with the modules and hosts.
 

Encap

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I'm wondering about the beam spread, though. I can get it pretty tight up fairly close. As the distance increases it starts getting more rectangular. If I'm understanding right, it's because these are actually a number of diodes set in a line to get the intensity? What I'm NOT understanding is how those lasers you see on the videos popping balloons and lighting matches across a room keep such a tight beam.

I guess next step for me will be building my own driver. Need to get more tools before I can get into any sort of host fabrication...
No there are not a number of diodes --- just one.

You adjust the focus of the beam ttightly as possible narrowing it with a collimation lens the screws into the front of the DTR module


It looks like it's made up of a line of squares, which is why I thought what I did. Thanks for pointing that out, learned something new.

Still leaves me with the question about how they do it in all those videos. They still look like a spot clear across a room. From what I read, you CAN do something about it with various lenses but it doesn't seem like something you could do in a single portable construct.

What lens did you buy with the NUBM44V2 module from DTR
Did you buy a lens? If you did, you didn't say which one or are you using it without any lens?

If you look at DTR's lens page and scroll down you can see the rectangular dot shapes created by an NUBM44V2 diode collimated using the different lenses DTR offers. Examples G2.G3, G8, DTR3E-B. See: https://sites.google.com/site/dtrslasershop/home/glass-lenses
 
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tony23

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No there are not a number of diodes --- just one.

You focus/narrow the beam as tightly as possible narrowing it with a collimation lens the screws into the front of the DTR module
I have learned that it is only one diode since the original post and I understand about slow and fast axis now. I have a lens, several, in fact, because I wanted to see for myself the various results.

At the moment I am using a G8. You can see it them on the emitting ends of the hosts in the photo.
What lens did you buy with the NUBM44V2 module from DTR
Did you buy a lens? If you did, you didn't say which one or are you using it without any lens?

If you look at DTR's lens page and scroll down you can see the rectangular dot shapes created by an NUBM44V2 diode collimated using the different lenses DTR offers. Examples G2.G3, G8, DTR3E-B. See:

I have all of those, actually, except G2.

After being pointed to the right information, I understand now WHY it forms the rectangular shape. The "multiple squares" is something I'm seeing, could be just an optical illusion, or may be something else. I'll explore that later.

I'm still too new to post links, but after searching on "fast and slow axis" I found a few websites that showed different ways to "square" that rectangle, one being the Laser Beam Collimation article at Integrated Optics, specifically the section "Ellipticity and methods to circularize a Laser Beam" and beyond. So there's either multiple lenses, or a lens and a couple prisms. I've also found several places that have the various types of optics I would want. So it looks like I may be able to do what I'm trying to do, but not in a single handheld package.

So what I'm trying to understand is: how do the lasers on the videos I see (where they pop a row of balloons and light a match across a 20-30 foot or longer space) keep their beams so tight? I don't see anywhere near as much spread in those videos as I'm getting with the G8 (which, per DTR's examples is the tightest), and those are single assemblies. It could be as simple as "those videos are fake" but I have no reason to conclude that just yet.
 

Encap

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tony23:
Different lasers have different wavelength, energy density, divergence characteristics, beam size and quality, dot size and shape. Re: videos of balloon poping: Unless you have the same laser with the same diode and lens and same balloons in same color your results will be different and your laser beam and dot will not look exactly the same.
If you were looking at green 532nm lasers they are DPSS and not direct diode. They have a much higher quality tighter more concentrated/higher power density beam and make a round circular dot that you will never get from any diode.

The NUBM44V2 has the worst divergence of all the blue lasers however, it should have no trouble popping a line of ballon.s
Maybe you damaged or ruined your diode if you can't pop line of balloons with either of your lasers one being 1.6W 45onm and one being a 7W 445nm laser. Who knows.

Popping balloons is not a big deal or trick thing--even little kids have made videos about same.
Here is one of a child popping 50 balloons in a row with a 3.8W 450nm laser see:
Here is LPF member "styropyro" popping 24 balloons in a row with a 2W 445nm laser
I have never seen a video of a hand held laser popping balloons that is fake, although there might be one.
Watching balloon popping videos is not my interest in lasers and I don't watch them generally.
There are dozens of them on YouTube and there is no reason to believe they are fake or that you can't do the same .

Focus the lens to infintiy and pop away.

Here is a National Science Foundation video about balloon popping with lasers see:

Do you understand that laser beam has no temperature? There is no inherent "temperature" to a laser beam.
Heat is produced by the random motion of matter particles (atomic or molecular particles). A laser beam itself is not made of matter but of photons, which have no mass, thus a laser beam can have no temperature. "Heat" is caused by a laser beams energy being absorbed by a materials surface and turning light energy into heat energy which depends on many factors. efficiency of the target's absorption of the laser wavelength among others-The ability for a substance to absorb a particular wavelength is dependent on the substance itself--its absorption spectrum.

PS Hope you have a good pair of laser glasses/goggles --they are a must for eye safety. A Survival Laser Eagle Pair are low cost excellent laser hazard eye protection glasses. https://www.survivallaserusa.com/Safety_Goggles/cat1667093_1527285.aspx
 
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CurtisOliver

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Doesn't matter really. DTR used 26 AWG. Such a minor thing to consider. As long as the wire grade is designed to take the current load you are fine. 26 AWG is more than enough usually.
 

CurtisOliver

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It is the gauge of the wire. The thicker the wire the more current it can handle. For your purposes thin wire has been fine so far.
 

tony23

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tony23:
Different lasers have different wavelength, energy density, divergence characteristics, beam size and quality, dot size and shape.

The NUBM44V2 has the worst divergence of all the blue lasers however, it should have no trouble popping a line of ballon.s
Maybe you damaged or ruined your diode if you can't pop line of balloons with either of your lasers one being 1.6W 45onm and one being a 7W 445nm laser. Who knows.
It's not the balloon popping that I'm concerned about, it's the beam divergence. I was just using that as an example. I suppose with the above you have answered my question. If I want THIS beam more focused it looks like I'll have to do it outside the host.

For future reference, could you suggest how best to determine divergence when selecting diodes? Pics of the beam, I guess - anything else?
Do you understand that laser beam has no temperature? There is no inherent "temperature" to a laser beam.
Heat is produced by the random motion of matter particles (atomic or molecular particles). A laser beam itself is not made of matter but of photons, which have no mass, thus a laser beam can have no temperature. "Heat" is caused by a laser beams energy being absorbed by a materials surface and turning light energy into heat energy which depends on many factors. efficiency of the target's absorption of the laser wavelength among others-The ability for a substance to absorb a particular wavelength is dependent on the substance itself--its absorption spectrum.
Yes, this is basic physics. Did I somehow give the impression that I thought otherwise? If so it was certainly inadvertent.
PS Hope you have a good pair of laser glasses/goggles --they are a must for eye safety. A Survival Laser Eagle Pair are low cost excellent laser hazard eye protection glasses.
Absolutely. Had them before I had the lasers. Nobody in the house is allowed to be around the lasers without wearing them.

Shifting gears, I'm curious about the "squares" I see in the beam - especially at a distance (it's pretty visible around 100 feet or so). I'm guessing it's some sort of interference pattern then?
 

gazer101

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Pretty sure that's a back reflection of the metal part of the laser die
 




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