Reason for more powerful diodes having higher divergence.

[_xXx_MLG_PiNgU_69420_xXx_]

I guess the diode in your Gatling is set back a bit, too far back to collimate to infinity with that lens, the G2 has less than a 3 mm focal length to reach infinity focus, 2 point something, thus the "2". I should know, I'm loosing it, forgetting. I can now see why you want a shorter FL lens.

No, it isn't, I can focus it to infinity perfectly fine (just over 2mRad). It's just that the beam gets cropped by quite a bit because the raw output has 120° divergence for some damn reason. Might just be a defective diode. I'm probably better off just buying or building something else entirely. Already ordered a 1W 520nm PL-E Mini, that should be a good replacement.
Actually, I never even intended to buy a gatling. I was going to do a 1.8A PLTB450B C6 build, but because I was talking so much about lasers, my dad bought me the gatling as a birthday surprise, but only told me when I had already ordered the G7 lens. It was cool for the first couple of days, but then, the lens got really fuzzy and I couldn't clean it, so I popped in the G7. The focusing mechanism is really loose too, and the lens keeps getting slightly off focus every few days, the heatsinking is pathetic, a ~2cm diameter brass disk with a not-so-heavy aluminum host, the included batteries were garbage, I ended up spending an extra 45€ on this thing, some 11€ for the lens and 33€ for some quality 16340s. I swear it just keeps giving me headaches. At least I can use the batteries with the PL-E Mini.

 

[Wakrah]

I bought a red Gattling pointer just for the fun of it, two months later and still not here from China 120 degrees, wow.

I've heard good things about the PLE mini. Did you order the beam expander option with it?

 

[_xXx_MLG_PiNgU_69420_xXx_]

I bought a red Gattling pointer just for the fun of it, two months later and still not here from China 120 degrees, wow.

I've heard good things about the PLE mini. Did you order the beam expander option with it?

Yeah, the raw output hits the damn heatsink itself (the diode is 1-2mm recessed in it because I accidentallly pushed it once, just had to readjust the infinity focus, no big deal), and about 1cm on each side of the host. Here are some images of the raw diode output inside the host, and of the cropped beam with the lens touching the heatsink, it's very fuzzy because I just used the original lens instead of unscrewing the G7. You can somewhat see the curved edges of the beam. I think I might have screwed up the math a bit, after another look it looks more like 90º, which is still extreme for a blue of this power. I guess it just doesn't really affect the divergence because the inital beam diameter coming out of the lens is the max possible.

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Apparently even a NUBM44 only has like 60º in comparison, with the NDB7875 having 44º. The PLTB450B, which is the diode they most likely use in the Gatlings, is supposed to have only 23º. All these numbers are for the fast axis, according to datasheets I found online. Apparently the fast axis turns into the slow axis after being collimated, when focused to infinity, so the lower the slow axis divergence on the raw output is in comparison to the fast axis, the more divergence the diode will have. I have no proof of this, I'm just making an assumption, as the PLTB450B, M140, and the NDB7875 have almost the same divergence, and also the same ratio between fast and slow axis divergence. The PLTB450B is 23ºx7º on average, while the M140 and the NDB7875 are both 44ºx14º, pretty similar ratio on all 3 (fast axis angle is about 3.2x the slow axis angle). The NUBM44 is 60ºx10º, which is about double the ratio of the other 3 (about 6x), and coincidentally its divergence is also about double. I think I figured it out.

Also, no, I just ordered the laser itself and some goggles, I personally don't feel like the beam expander is necessary with that diode's divergence. Also apparently it kinda crops the beam on non-DPSS lasers or something.

 

[Wakrah]

Photobucket has been highly unethical to indivduals in the past, holding full resolution photo's randsome for hundreds of dollars, I wouldn't use them due to their past behavior. Regardless, when I click the link I only see an advertisement to join.

For myself, I just go for the most luminosity I can get with decent divergence, a beam from a 1 watt green laser can be just as bright as a 7 watt 450 nm blue. I bought myself a 10 watt DPSS 532 nm green laser last year I don't need, just love power at that wavelength. I'd love to see what it looks like into the night sky, but don't want problems, so have never done so. If I lived in Alaska I'd do it, but not here in Qatar. So far, doesn't seem much I offer is helping though, you already understand so much.

 

[_xXx_MLG_PiNgU_69420_xXx_]

Photobucket has been highly unethical to indivduals in the past, holding full resolution photo's randsome for hundreds of dollars, I wouldn't use them due to their past behavior. Regardless, when I click the link I only see an advertisement to join.

For myself, I just go for the most luminosity I can get with decent divergence, a beam from a 1 watt green laser can be just as bright as a 7 watt 450 nm blue. I bought myself a 10 watt DPSS 532 nm green laser last year I don't need, just love power at that wavelength. I'd love to see what it looks like into the night sky, but don't want problems, so have never done so. If I lived in Alaska I'd do it, but not here in Qatar. So far, doesn't seem much I offer is helping though, you already understand so much.

I had no idea about that, I just used the fist website I saw, as I couldn't find the upload on Imgur.
Tried another site, here you go:

IMG-20210124-111518-1 hosted at ImgBB

Image IMG-20210124-111518-1 hosted in ImgBB

ibb.co

IMG-20210124-111642 hosted at ImgBB

Image IMG-20210124-111642 hosted in ImgBB

ibb.co

 

[Wakrah]

I see a big rectangle in the center with all of that fuzz surrounding it, I guess that is being caused by the reflections off of the side of the aluminum in the center where the beam shoots out. Those are well known in the forum to be about as low quality as you can get in a laser pointer, but they sure look cool and can be had very cheaply. Although some sellers mark them up several times higher than normal, they still get bites anyway, just because of how cool they look in the photographs.

For forum photo's I only use www.imgbb.com anymore.

 

[_xXx_MLG_PiNgU_69420_xXx_]

I see a big rectangle in the center with all of that fuzz surrounding it, I guess that is being caused by the reflections off of the side of the aluminum in the center where the beam shoots out. Those are well known in the forum to be about as low quality as you can get in a laser pointer, but they sure look cool and can be had very cheaply. Although some sellers mark them up several times higher than normal, they still get bites anyway, just because of how cool they look in the photographs.

The fuzz is due to the lens, the raw output is pretty clean despite being waaaay too divergent. The point of that photo was to see the curved edges of the rectangle, indicating that the output is cropped, even with the lens as close as possible to the diode.

 

[Wakrah]

OK, I see it now, yep. Seems the lens is too close, causing the beam to be too wide, and that is what is causing the cropping, not at infinity focus.

 

[_xXx_MLG_PiNgU_69420_xXx_]

OK, I see it now, yep. Seems the lens is too close, causing the beam to be too wide, and that is what is causing the cropping, not at infinity focus.

That just makes no sense, the closer the lens is, the smaller is the captured beam, reducing the cropping. The cropping is just barely noticeable in this photo, but when I slightly adjust the focus from infinity you can easily see the round edges of the spot. the diode is also slightly off-center in relation to the lens, the beam is shaped like this: / \, just imagine the slashes are part of a circle. Here's a photo of it:

IMG-20210124-145852 hosted at ImgBB

Image IMG-20210124-145852 hosted in ImgBB

ibb.co

 

[Wakrah]

If you take a lens and hold it at the right distance from the diode to produce infinity focus, moving it closer, or further way from that focus and the beam gets larger, each direction, whether closer or further away. Isn't that what you are seeing? You could also pull the lens into a position where the beam produces a tight focus where you can burn, the beyond that spot, the beam will diverge again, if nothing is in front.

 

[_xXx_MLG_PiNgU_69420_xXx_]

If you take a lens and hold it at the right distance from the diode to produce infinity focus, moving it closer, or further way from that focus and the beam gets larger, each direction, whether closer or further away. Isn't that what you are seeing? You could also pull the lens into a position where the beam produces a tight focus where you can burn, the beyond that spot, the beam will diverge again, if nothing is in front.

Oh you're talking about the collimated beam, I was talking about the raw output, which leads to cropping if it's larger than the lens, which happens when the lens is farther away.

By the way, the laser used to ignite white paper when focused, now it will only make some embers. Even with the G7, which is supposed to be like 25% more efficient. No idea why that happened.

 

[Wakrah]

Your thought the diode has damage may indeed be the reality. I'm looking forward to seeing you post about your JetLasers PLE-mini, when will you get it? I'd get the beam expander someday, it really helps if using the pointer outside, if that isn't a problem where you live. I see the divergence is 2 mRad, not terrible, not great.

 

[_xXx_MLG_PiNgU_69420_xXx_]

Your thought the diode has damage may indeed be the reality.

One time, a few days after I added some tape to the lens holder's threads, a little piece fell right on the diode with the laser on. I immediately turned it off, there was no permanent damage, most of the residue came out with an alcohol soaked microfiber cloth, there are like 2 barely visible little spots left. That's also when I pushed the diode inwards by a milimeter or so. However, that didn't change the divergence, it was still the exact same before that, and I also couldn't ignite white paper. It's still no slouch, it scorched my wooden door from 7.5m away when focused to the thinnest line possible at that distance, but something definitely happened.

EDIT: My question still stands. Imagine 2 different lenses, one with half the focal length of the other, with the same diameter. Would one laser using the longer focal length lens, and the other using the half FL lens, but with twice the raw output divergence, therefore both lasers have the same initial beam diameter after passing through the lens, have the same divergence? For example, imagine one diode with arctan(2) raw divergence, using a lens with 10mm focal length and 25mm diameter, having a beam diameter of 20mm at the lens, and another diode with arctan(1) divergence, using a lens with 20mm focal length and 25mm diameter, also having a beam diameter of 20mm at the lens, have the same divergence?
Basically, is the beam diameter at the lens the only thing that matters?

About the PL-E Mini, I ordered it yesterday, If there isn't any trouble with customs it should be here within 2 weeks I assume.

I have another question. Imagine you have a diode with an extremely high divergence, which gets cropped quite a bit, and one with the perfect divergence so as to be as wide as possible without being cropped by the lens. Both use the same lens. Would they have the same divergence, seeing as the more divergent part of the beam in one diode gets clipped?

 

[Unown (WILD)]

I'm probably late in saying this but a lot of these diodes are made for projectors. The output is the way it is for video aspect ratios of 16:9 and up