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Here is the best image I can get to upload. I will send the diode back to DTR so he can inspect it and decan it for me. Thank you.
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NUBM44 6W+ 450nm Laser Diode
- Thread starter DTR
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The diode window may have cracked where the beam exits, circular crack, but the 1/4 thick copper ring in the front encircling the 12mm housing dissipates into a lot of aluminum and I also have copper at the back of the module that contacts a lot of aluminum. It is not hot after running for 60 seconds. The contacts on my cheap battery box are hot but not the diode. I suspect the diode window may be failing, but I could be wrong. Usually I fill the 12mm housing with heat sink putty to draw heat off the back of the diode as well but this time I didn't as I only put it into a test bed so I could work with my box of optics and beam expanders as the divergence is significant.
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DTR
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Yea what you see as a circular crack is a hole melted in the glass. These diodes push enough power though that tiny spot to melt a hole straight through glass when it can't get through.
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Extraction method is pretty clean. There would not be any excess dust or other particles being created due to it over other methods used for other pulls like the M140. I just checked all the ones I have extracted here and they are all spotless under my microscope. I do also power every unit including bare diodes to make sure they don't have anything obstructing the light path. Are you seeing anything in the output when you power it just to lasing threshold. That is how you can check without running the risk of burning anything on it.
Are you still using a dremel to cut away the block? Did you see my post in the vet section about heat, and did you give it any thought?
DTR
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No dremel. Yep if the solder is heated up it will melt.
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So I finally got around to testing, characterizing, and compiling data for the diode I got. Here's what I found.
Gentech TPM-310 power meter
Sorensen XT7-6 bench power supply
Science Surplus Spectrometer
Plotted in excel
The beam was 140mm at 11.5m, which put the divergence at 12.2mRad.
I got it down to 2.7mRad with a single uncoated prism I had lying around, but the losses were ~36%
Gentech TPM-310 power meter
Sorensen XT7-6 bench power supply
Science Surplus Spectrometer
Plotted in excel
The beam was 140mm at 11.5m, which put the divergence at 12.2mRad.
I got it down to 2.7mRad with a single uncoated prism I had lying around, but the losses were ~36%
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It's crazy that I have so many lasers across the visible spectrum and still haven't bought a LPM but I can tell you that it was kicking out mondo power. It was lighting big wooden matches in the middle at 5 feet in 2 seconds flat focused to a line about a 7-8mm long 1mm wide and instantly bursting out a flame on anything wood at 18 inches when focused. Wet green leaves had a 1 inch long line burned through when focused at 15 feet about as fast as the 7875's so based on the line size it must have been putting down 2.5 times the power of my 7875's. Yea it was kicking ass but I must have gotten a fleck of something on the window because it was putting out a solid gorgeous blue ribbon when I turned it off yesterday. Today at a cold start it was bubbled. It's almost like it cracked while cooling down, kinda like glass projector bulbs do if you ever touch them or get something burned onto the glass that weakens it. Anyway it's in the mail to you now so you can get a look at it yourself, and thanks for decanning it for me. I will run it open and see how long it lasts. Next one I buy will be kept clean and cool.
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VG...I use 6x Cylindrical lenses. Theory sez 4x will perform..,,but I like
6x...and I prefer a larger lens...as seen in my test bed setup. A larger lens means the lenses are easier to handle and position....and they are slightly more forgiving on the side to side alignment.
I know that 3.5x is not enough to correct the P-73...and I have done perfect correction with 5x to correct the P-73.
I do not have a set of 4x...but...I would predict they will work...but...I am not 100% sure.
Check out Post #197/#199 in this thread for some optical/correction info on this diode. I will machine a LD heat sink/Cylindrical Optical lens unit...and post the details when done.
Again, the NUBM44 is correctable...
!!!!!Using the Pseudonomen 137's mRad Calculator for laser divergence...with a Near Field width of 1mm and at 25' (7.6M) ....a farfield
width of 10.76mm.... the beam divergence calculates out to 1.28mRad !! That is OK !!! Not great....but fairly good....and I would predict optical loses at 1~3%....No free lunch....
And thanx for the very professional graph's Cyp !!....We add knowledge as we push forward !!!
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DTR
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Yea that is why I have not tried a heat extraction yet.
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If you aren't cutting them out or using heat, does that mean thet just pop out? I wondered if it would be worth making a threaded extraction tool (like what FP makes), then tap a small portion of the "diode barrel," if you will, and pop them out that way. Seems like a lot of work, but it seems like it would work great.
DTR
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I found a great method that is similar along those lines but I will warn you don't use anything that puts direct pressure on the base of the diode to push/pop it out as it will warp and break the diode. lost one that way when trying to figure out a method.
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Hmm, good to know. Well, not really as I won't be tearing down one of these projectors (probably ever, unless if they can be had cheaper second hand at some point). Do you have a hot air gun by chance? Also should I move this to pm?
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I should point out that no, that is not one of these blocks. That video is 4 years old...
It is very hard to clean optics, I mean really clean them. A good rule it to never let them get dirty! If you have to, canned air is a pretty good, non-contact method, but make sure you short the leads as high velocity air (with debris) can generate a significant voltage. Use a loupe to inspect the optic and I have found a common wooden tooth pic can move or stick to a particle that I am afraid to wipe across an optical surface. A dedicated spray bottle with super pure, spectroscopic grade or at least reagent grade acetone or methanol can blast dirt off complex surfaces, avoiding the need to wipe. Methanol is safer and less aggressive toward potting compounds and adhesives.
I agree that temperature is not likely my problem, but testing another diode in two different hosts should clear that up
CD,
Where are you measuring your near field, relative to the diode face? What does the correction do to the power?
With these very divergent diodes like the P73, you can adjust the magnification ratio of your cylinder pair simply by varying the distance from the diode. As you increase this distance the first cylinder is struck by the same ray angle, but further from its axis and so becomes more powerful. Consequently the second, positive cylinder has to be spaced further from the first lens, increasing the magnification.
I agree that temperature is not likely my problem, but testing another diode in two different hosts should clear that up
CD,
Where are you measuring your near field, relative to the diode face? What does the correction do to the power?
With these very divergent diodes like the P73, you can adjust the magnification ratio of your cylinder pair simply by varying the distance from the diode. As you increase this distance the first cylinder is struck by the same ray angle, but further from its axis and so becomes more powerful. Consequently the second, positive cylinder has to be spaced further from the first lens, increasing the magnification.
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PT...For divergence calculations...I am measuring the Near Field as it presents on the first/closest surface of the first Cylindrical lens.....so...essentially....measurement occurs at 2mm from the LD window.
And yes....the magnification of the Cylinder Telescope set is a function of the separation distance between the LD window and the first Cylinder lens.....but....as I previous explained....to the Non-projector group....the Near Field.....as measured past the second Cylindrical lens is likely too wide for most scanner mirrors !!
Concerning power loss due the use of the Cylindrical lenses...I have not yet measured the loss with the NUBM44. I will note that optical loss when correcting the pP73/HL63193 is really minimal....like 1~3%.....so....I assume it is likely the same loss as it is with the P73/HL63193
Perhaps my methodology is flawed ??? Please advise ! Thanx...CD
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