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Difference between lenses?? Gball/G2/G3/G7 etc.

DackJaniels

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Hey guys I've been poking around looking at different lenses for lasers but I haven't really found any info on the differences between a glass ball lens and the g2, 3, 7 etc lenses. When it comes to divergence and power, how does the glass ball lens compare to the g2, g7 and 3 element lens? I've also heard that removing the gball could lessen the life of the laser? Is that true and why?
 



TinLethax

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These informations are for the 3E,G2 and G7.From Sanwu Laser source is here.
====================================================================================================================
3-element lens (Cleanest beam profile, best for low power lasers)
3-element lens has a long focal length, low divergence and clean beam profile but it has a significant output loss.

AdvantageTight laser beam with the cleanest beam profile
Downsides 70% efficiency (1W diode = 700mw using this lens)

G2 lens(best for power)
The G2 is a single lens enabling the maximum true power of the laser diode for rapid close-range burning and engraving.

Advantage95% efficiency, reduces the beam aperture
Downsides Increases the beam divergence (thickness) and the beam profile

G7 lens(Balanced Multi-Purpose Perfection)

This lens is a cross between the divergence and the power lens. With the G7, the beam divergence won't increase as it does with the G2 and you will still get very close power of the laser diode.

Advantage 88% efficiency, long focal length and increases beam apertrue
====================================================================================================================
 

RedCowboy

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The G7 is a long focal length single element lens and I liked the concept, but in our high quality copper modules it focuses out at the last turn of threads, it has no retainer and is sometimes not straight, and the lens barrel is sometimes too wide, however there is a new lens the DTR G8 and it catches much better thread wise.

Here's some numbers I just posted in another thread > https://laserpointerforums.com/threads/dtr-g8-lens.104214/post-1557753
 

DackJaniels

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So 3 element divergence with almost as much power as a G2? That's very impressive thank you for the reply!
 

RedCowboy

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Yes, it appears to be everything I hoped the G7 would be and it has a seat and retainer, that is it's not a press-fit/glue-in like the G7
 

Lifetime17

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Hi, Red just did an evaluation. on the G2/G3 and G8 lenses . there is a thread on it, I doesn't include the G7 I think..

Rich:)
 

RedCowboy

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The G7 has an even longer FL than the G8 but it's too long for our high quality copper modules thread depth, it only catches 1 turn of the threads and the G7 is also pressed into it's lens barrel, it has too many problems, the G8 is a much better choicc IMHO
IIRC power output was better than 3 element but less than G2 although no better than the G8.....did I mention I like the G8 :D
 

Lifetime17

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Hi Red,
sounds like a winner like you said I am in for them , I include the G2 lens in all my builds unless other wise from the customers preference.

Rich:)
 

RedCowboy

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still no one gave the answers to the questions asked!!!!
Hey guys I've been poking around looking at different lenses for lasers but I haven't really found any info on the differences between a glass ball lens and the g2, 3, 7 etc lenses. When it comes to divergence and power, how does the glass ball lens compare to the g2, g7 and 3 element lens? I've also heard that removing the gball could lessen the life of the laser? Is that true and why?
Removing the GBall lens from multi watt blues will shorten the lifespan., I had read about why some researchers think this happens and it's basically exposure to the air/contaminants/humidity and micro cracks that develop on the facet as well as facet damage from reactions with air/humidity as well as a possible build up on the facet from product with air while lasing.
If you search you should be able to find other threads where I posted a link to the research, I don't have the link at hand.

The GBall lens appears to be very efficient ( about 95% ) but they appear to not all be the same from what I have seen, for example some blocks of nubm06 with the GBall lens cans will be pretty close to focused making a small spot on the wall 10 feet away while another block of nubm06 with what looks like the same GBall lens and can ( same can length ) will not be focused much at all making a large spot on the wall, I expect this is because of a different lens grind/shape and I would think that the OEM would order blocks with the focus they want for their device, or placement in the can and/or the thickness of the indium foil that bonds the can to the diode could be of varying thickness.

I have shortened the GBall can and placed the lens into a threaded barrel so I could focus a diode with the lens and it was not giving me the tight beam waist that we can get with our other lenses, I'm not sure why as I break them when attempting to remove from their cans, I don't think they are very useful for our purposes but if you find otherwise please do share. I think Badboybilly said he had used one in a threaded barrel and it was nothing special, but again I don't think they are all the same so it's possible that one example may work better than another, I have not had any luck reusing them once removed.

G2 is a single element aspheric broadban coated short focal length, divergence is not as good far field because of it's short focal length but up close it's the best for home CNC or for use pre beam shaping optics. It passes the most power and is the LPM testing lens of choice. Passes about 95%

G3 Similar to G8 but a smaller diameter lens in a regular size M9x0.5 lens barrel with a smaller opening, it passes less power than the G8, about the same as a 3 element but is cleaner than 3 element, it's a single element long focal length broadband coated. Passes about 70%

3 element is a multi element with good divergence but some clipping and the most power loss of the glass lenses. Passes about 70%

G7 is a single element long focal length making divergence good but not as good as the 3 element or G8 and the lens is pressed/glued in making it a trouble prone lens. Passes about 85%

G8 everything the G7 was supposed to be and then some, my new favorite, it's a single element broadband coated long focal length with the best divergence. Passes about 90%
 
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paul1598419

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I believe the ball lenses are spherical. This is why they are not anything "special". It is hardly worth one's time and effort to incorporate it into a lens holder.
 

RedCowboy

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I believe the ball lenses are spherical. This is why they are not anything "special". It is hardly worth one's time and effort to incorporate it into a lens holder.
Right paul I think it's a ball type lens, I just have not been able to remove the lens from the can without breaking it but I have not tried but a couple of times.

You know I talked about this a while back and someone said it wouldn't work, but I think it will and after reading THIS I am even more convinced that this could work because we have done this with a backwards G2 then forward G2 following an intact GBall, but my original idea was to use a 2nd removed GBall from the same block then a normal lens such as G2 or G8

Granted the 2nd GBall from a sister diode would need to be placed into a threaded holder and the copper module would need to either be longer in it's threaded lens portion or we could use a coupler as I have demonstrated with using backwards/forward GBalls


Fiber to Fiber Coupling


63974



63972
 
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GSS

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still no one gave the answers to the questions asked!!!!
You didn't even post here???????? You need to chill..
Could be you have some issue's that cause your "just me only" attitude??:unsure: and if so I apologize but,,
Fortunately RedC is a gentleman and a wealth of info and goes above and beyond the norm of helping with putting time in his posts that you just don't see much these days.. Your lucky he was helping someone else on this thread to be honest too.. and he's the only one who helped you with your decanning question..;)
 

m3vuv

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my comment was a mere observation! i see all to often a thread gets sidetracked and the original questions remain unanswered,i was looking for the same info,read the whole thread and still no nearer!!
 

RedCowboy

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It's ok GSS my friend, I like to share info and learn myself, sharing info benefits us all.
Also you are much too kind, I am really not a proper gentleman but I try to play nice most of the time. :)


---edit---

It's all good m3vuv, a lot gets lost in the text, often things can come across as terse when they weren't meant to be when we read a short sentence.
 
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DackJaniels

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Right paul I think it's a ball type lens, I just have not been able to remove the lens from the can without breaking it but I have not tried but a couple of times.

You know I talked about this a while back and someone said it wouldn't work, but I think it will and after reading THIS I am even more convinced that this could work because we have done this with a backwards G2 then forward G2 following an intact GBall, but my original idea was to use a 2nd removed GBall from the same block then a normal lens such as G2 or G8

Granted the 2nd GBall from a sister diode would need to be placed into a threaded holder and the copper module would need to either be longer in it's threaded lens portion or we could use a coupler as I have demonstrated with using backwards/forward GBalls


Fiber to Fiber Coupling


View attachment 63974



View attachment 63972
Hmmm very interesting I'm very grateful for all the replies! What about when it comes to adding a focus to a diode with a gball? Is there a reason it can't be done or rather won't? Power loss? or would the beam but not focus right going through so many lenses? I thought a focusing adapter was merely slapped on. I figured light is light so a focus should work?
 




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