Using the Jetlaser's Beam Expander for high divergence diodes (eg 44)

[hoo7h]

Hi all,

So after a bit research and asking around, I found that some believe that the Jetlaser's beam expander isn't really suitable for a high divergence diode such as the 44 or the 7475, as the beam might be clipped.
In other words, choosing the Sanwu BE for such a laser is probably the wiser choice for these high divergence builds. What do you all think?

Also in a side note, what do you focus your primary lens at when using a beam expander (I have a PL-E mini 520nm green)? I am not sure if I am doing the focusing correctly. Do you set it in for the shortest focal point possible or the longest?


Cheers,
H

 

[RedCowboy]

You can short focus your primary on the stage 1 divergence MM diodes, that is NDG7475, NDB7875, M-140, PLPM450B and the old 1 watt pretty well but you are cutting the full potential of 10X short, the higher divergence such as NUBM44 and NUBM08 are hard to get more than half the power out in my experience, I did focus a what I call ( stage 2 ) divergence NUBM07 to 7 feet and got a rectangle ( Tight burning one ) at 15 feet with the Jet 10X but far field you can see the beam bouncing of the inner walls of the BE.

When you put a diverging rectangle beam in and get a round beam out you can well bet you are clipping and wasting power.

The input lens diameter and output lens diameter are too small to hold 10X with the more divergent MM diodes, especially when optically corrected, in my experience.

For example a 6X cyl corrected NUBM44 with a G2 primary makes about a 7mm wide ribbon beam that is wider than the input and even if it would accept the full 7mm beam width the output lens is not 10X the input much less 10x 7mm i.e. 70mm and you want that to occupy 80% of the output/objective lens.

Some people have had decent results with stage one divergence MM diodes, Lifetime17 built a NDB7875 with the 10X that worked pretty well but I believe he had to short focus ( less than infinity ) the primary and it was not a corrected beam, however he got good results.

I would not use it for the NUBM44 or NUBM08 and I really don't like it for any of the more divergent MM diodes, I have a NDB7875 with a G2 and Sanwu 3X that works very well, and you can short focus those stage 1 divergence diodes and still get maybe a 5X equivalent from the 10X ( ESTIMATED ) but I don't know how much of the 7A75 or 05/06/07 you can actually get through and how short you would have to focus your primary, in my opinion the lens diameter both input and output are too narrow to get the full 10X out of an infinity focused primary or corrected beam from anything other than DPSS and stage 1 and possibly stage 2 divergence MM diodes without short focusing the primary which means short changing the 10X vs an infinity focused beam and the 3XBE or a BE with wider lenses for the magnification power.

But this is just my experience, someone with a LPM who has a 10X on a 07 or 7A75 could tell you what they get at 100 feet, now you can cheat it to work short range such as I did with this 07 at short distance, but that's not really the purpose of a big BE, it's to reach way out and that's where it seems to fail with the more divergent MM diodes. ( In my experience. )

p.s. It may be possible to use some correction and then telescopic reduction before the 10XBE but as one lens can effect the next I don't know how well that would work, also the more glass in an optical train the more parasitic loss, much can be mitigated with proper AR coatings although any uncoated lenses can eat up around 5% each from what I have read. A wider input/output lens expander to achieve 10X would be my recommendation for use with our more divergent MM diodes, or step down on mag to the 3X and keep the lens diameter more manageable.

 

[hoo7h]

You can short focus your primary on the stage 1 divergence MM diodes, that is NDG7475, NDB7875, M-140, PLPM450B and the old 1 watt pretty well but you are cutting the full potential of 10X short, the higher divergence such as NUBM44 and NUBM08 are hard to get more than half the power out in my experience, I did focus a what I call ( stage 2 ) divergence NUBM07 to 7 feet and got a rectangle ( Tight burning one ) at 15 feet with the Jet 10X but far field you can see the beam bouncing of the inner walls of the BE.

When you put a diverging rectangle beam in and get a round beam out you can well bet you are clipping and wasting power.

The input lens diameter and output lens diameter are too small to hold 10X with the more divergent MM diodes, especially when optically corrected, in my experience.

For example a 6X cyl corrected NUBM44 with a G2 primary makes about a 7mm wide ribbon beam that is wider than the input and even if it would accept the full 7mm beam width the output lens is not 10X the input much less 10x 7mm i.e. 70mm and you want that to occupy 80% of the output/objective lens.

Some people have had decent results with stage one divergence MM diodes, Lifetime17 built a NDB7875 with the 10X that worked pretty well but I believe he had to short focus ( less than infinity ) the primary and it was not a corrected beam, however he got good results.

I would not use it for the NUBM44 or NUBM08 and I really don't like it for any of the more divergent MM diodes, I have a NDB7875 with a G2 and Sanwu 3X that works very well, and you can short focus those stage 1 divergence diodes and still get maybe a 5X equivalent from the 10X ( ESTIMATED ) but I don't know how much of the 7A75 or 05/06/07 you can actually get through and how short you would have to focus your primary, in my opinion the lens diameter both input and output are too narrow to get the full 10X out of an infinity focused primary or corrected beam from anything other than DPSS and stage 1 and possibly stage 2 divergence MM diodes without short focusing the primary which means short changing the 10X vs an infinity focused beam and the 3XBE or a BE with wider lenses for the magnification power.

But this is just my experience, someone with a LPM who has a 10X on a 07 or 7A75 could tell you what they get at 100 feet, now you can cheat it to work short range such as I did with this 07 at short distance, but that's not really the purpose of a big BE, it's to reach way out and that's where it seems to fail with the more divergent MM diodes. ( In my experience. )

p.s. It may be possible to use some correction and then telescopic reduction before the 10XBE but as one lens can effect the next I don't know how well that would work, also the more glass in an optical train the more parasitic loss, much can be mitigated with proper AR coatings although any uncoated lenses can eat up around 5% each from what I have read. A wider input/output lens expander to achieve 10X would be my recommendation for use with our more divergent MM diodes, or step down on mag to the 3X and keep the lens diameter more manageable.

This is super informative. I am working with someone to perhaps make a 6x correction cylinder, and will probably just go with the Sanwu beam expander.

Thank you very much!

 

[Lifetime17]

hi,
I don't know about the divergence part but i made a 44build with a 10X Jet and when focused it burnt a hole in a dark tee shirt at 32 ft in 5 seconds.

Rich

 

[Alaskan]

I tried RedCowboy's trick with that beam expander with a NUBM44 by adjusting the laser out of infinity focus, so that it could pass through the input side of the expander and it helped a lot, but the expander appeared to be truncating or cutting off a fair amount of the beam, as he also observed.

 

[paul1598419]

Subbing. Might get interesting.

 

[Alaskan]

RCB, I thought your post was very good, don't know why you removed it, great info. Also, appreciate the way you helped me figure out how to use the JL expander with my multimode laser diode, that trick sure worked.

 

[RedCowboy]

@ Alaskan: I don't want to appear to be attacking anyone's work so I am trying to keep my facts straight, just one mistake or if I forget to qualify a thought with AFAIK, or IIRC then the drooling trolls lurking on the sidelines will pounce.

So let me say that I wish to share information and hopefully save others from having to learn the hard/expensive way, and I may well learn some myself, I often do. I am not attacking anyone's efforts.

If the 10X can take the G2 all up close at it's tightest without burning its AR coating or having to be short focused by too much in order to fit the output lens then we could realize 10X, granted it will be a line and not a dot but still a pretty good one, at 32 feet I would expect Lifetimes shirt to be on fire, because it looks like the bar is all there in a good sized line.

----------------------------------------------------

Lifetime17 has his Sinner Cypress II build but I cant find a thread on it, a lot of our older stuff is missing the pics ( Thanks a lot photobucket....NOT ) and for some reason I thought it was a 7875 but it may well be a 44 diode.

I read that someone used a 44 with a G2 primary and burned the AR coating on their Jet 10 so I never attempted to use that combo and when I used a 44/G2/6Xcyl pair I got a slightly larger bar at 32 feet but it burned through in 2 seconds, although my shirt was a faded black.

If the Jet 10X can take the 44/G2 putting it's 6.5 + watts into that small area on the input lens then I will buy another and try it, I know the Jet 10X could not fit my 6X corrected 44's 7mm wide beam as the input is 5mm or slightly less IIRC, but the Sanwu 3X can provided I use a Sanwu G2.

Here is Lifetime17's Sinner Cypress II from a 44 thread I made, I will have to go search on another laptop with chrome to see if I can find his thread.

https://laserpointerforums.com/f65/...pts-videos-builds-more-97325.html#post1420567

 

[paul1598419]

That is odd. That host does look like a Cyrpus II, but it is aluminum. I have one made completely with copper and though it is a much better thermal conductor than aluminum, I still would hesitate to put a NUBM44 in it. The Cyprus is small compared to other sinner hosts, like the Envy and the MS-SSW-II. I can't help but think the duty cycle on it must be very short.

 

[GSS]

hi,
I don't know about the divergence part but i made a 44build with a 10X Jet and when focused it burnt a hole in a dark tee shirt at 32 ft in 5 seconds.

Rich

Oh no Rich...don't tell me accidently burnt your favorite Bee Gee's T shirt:can:

 

[Lifetime17]

Hi,
Red,
Yes that was a great moment burnt through in seconds i will find out what diode it was it might be a NUBM44 so many builds i forget whats in some of them. I still have that build I'm sure it would do the same at a further distance .
@ GSS,
Bee Gee's not never sorry not for me buddy, maybe Cream, Traffic, Yardbirds, CSNY, Floyd along those lines..
Rich

 

[Andrew124C41]

Maybe you guys can clarify something for me. When I was out the other night for the first time using the 10X Jetlaser, I was under the impression that a BE is a telescope in reverse. (either Keplerian or Galilean.) I have not been able to find out what type of expander the Jetlaser is. Anyway, I was under the impression that when you rotate the center and move the lens, you are simply changing the power of the BE.

After trying all sorts of different focus points of my primary lens....trying G2, 3 element, and 2 element, it seems as though the optics are not what I thought. I could got from expanding the beam to focusing the beam....ok...that may be no surprise....however, at one time I had it configured so that the beam focuses to a point midway to my target and then expanded towards the target if that makes sense. My point is that moving the lens is not simply changing power....when combined with the focus of the primary....it behaves differently.

Does anyone know what kind of lenses are in the Jetlaser BE?

Optics is not my strong suit :banghead: So, I am all ears.

I forgot this: Everything you wanted to know about beam expanders

 

[Alaskan]

@ Alaskan: I don't want to appear to be attacking anyone's work so I am trying to keep my facts straight, just one mistake or if I forget to qualify a thought with AFAIK, or IIRC then the drooling trolls lurking on the sidelines will pounce.

Tell me about it, say one thing wrong and there is usually one or two members who will instead of just helping out, appear to deeply enjoy dragging you through the mud for either not qualifying a statement correctly, or simply having a momentary brain fart!

 

[RedCowboy]

Andrew, you probably want to use the G2 and focus it to a sharp line at 5 to 10 feet ( Not recommended with the NUBM44 it could burn the lens coating ) ( and lock it down if you can, it may be moving on you and just a little movement changes a lot ), I use the end of a copper 12mm module to lock down the G2 focus, then put the 10X on and go back and forth through it's entire range and see if you have a section where you can zoom the spot in and out, then you can move the G2's focus further out or in if needed and see if your results are better, keep re adjusting the G2's focus until you find it is clipping, you should be getting a rectangle/line shaped spot, ( LOOK AT IT WITH YOUR SAFETY GLASSES ON MADE TO ATTENUATE THE WAVELENGTH ) if it's round then you are clipping and you want to move the G2's focus closer in......possibly out :/

Here's where I was testing it with a NDB7875, same divergence as your 7475, I decided to go with the 3X that is NDB7875 with a G2 set to 30 feet for best results where I use it, then the 3XBE and it works great, it will also work with the G2 focused to infinity, I just like it a little closer in, but with the 10X you will need to lock down your G2's focus and find it's range, when I set mine to 14 feet I got clipping.

Here's where I was working with the one I had.

https://laserpointerforums.com/f49/jetlasers-10x-rcb-97463.html

 

[Lifetime17]

Hi,Andrew,
Red is correct about setting up the 10X BE, once your primary lens is set then you can adjust the BE. Thats why i made these adapters so once you set the primary then you put the adapter on withe the BE . Once thats done with the adapter its a one hand operation . Here's a pic of an adapter ..

Rich

 

[hakzaw1]

BRINGING THIS THREAD BACK TO LIFE

(Almost) Sold my last JL 10X BE.. delivered in record time.
When I got my first BE I was banging my head trying to make it 'work' FOR WEEKS! If I had paid for it I would prolly asked for a refund BTDT.. it was a sample.

Kept at it==got good advice and now I am embarrassed about making such a big deal.
IF YOU own any JL BE please post your honest candid feelings--I think for price its very good.
AND one need not be limited to using ONLY on a Pro Pl-E... so that is news to me and I need to thank my 10X 'buyer' for that. Using a standard lens nut you can attach the JL 10X Be to many lasers!

Please answer these Qs.
At ~$100 ($95 duringsale) + or - plus JL DHL EXPRESS (no choice) at $37 for ship to USA.
and looking at the Sanwu and WL BEs ==how do they compare.? ( I have only seen JL BEs)

Do you have any doubt that the claim of being 10X by JL is correct?

How would you rate the quality (1 to 10 best)

and how experienced w/BEs are you?(1 to 10) w/ 10 being 'high'

IF the BE arrived in good condition would it still bother you if recycled packing was used?

would you NOT get a chuckle if the BE w/ its first layer of bubble wrap was enclosed in a Star Wars Snack bag (new) then inside paper envelope and then more bubble and inside small box.??


not running a charity here.

IMHO once aligned I would only remove my BE for important reasons..

why?
its a pita to realign
The BE 'protects' the front of the laser.
REPEATED removal and reattachment invites teeny weenie tiny bits of metal to potentially get on a lens.. clean it and it scratches the lens!
And the laser has a coolness factor increase of .6
kinda like a silencer on a gun..lol


last Q
you choose:
The BE still sealed untouched by me.
OR one that has been inspected and tested ONE TIME on a new JL Pro PL-E 1W 520 LD for function (not aligned)


IF there are any/many unhappy 10X JL BE owners out 'there' its news to me.
SPEAK UP PLZ

that being said I AM SOLD OUT!
FEELER for pop-up GB you pick JL 10X for Pro -PL-E
or Pro PL-E mini BE.
Savings will mostly be in your 37$ $hipping. I get them all and reship for less than $7 each buyer. $10 if two or more are shipped together.

Expect prices to be ~$99 for Pro PLE
and $ 89 for MINI JL BE.
Aiming for a buy of 10 pcs mixed.

I Most likely will pay with Western Onion and for each pcs add on ONE SHARE (~10%)of that fee...


WS has a deal that MAY still be going-- send up to $500 usd anywhere for $5. So would need to split the orders for 5 pcs each. I will use the best way.

New thread going up soon in the GROUP BUY section.. 1st come 1st served.

PM to be early birds on my list. atm I am not sure if these will be black only or a choice of silver grey as well.

hak