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Knife-edging four NUBM44 in Lasertack micro module

CDBEAM777

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Well....Humph....LSG/LS...." Even a Blind Dog finds a Bone "....now and then !!! I thought having the beam off centre as it passes thru the C-lens / Plano Concave might give us some problems ??

So.....If we rotate the LD's.... from llll to ---- AND rotate the C-Lens set..... 90 degree
All four (4) beams will propagate into the Plano Concave lens....on centre .... and we end up with our (4) beams.....side by side ..... looking like this
[ ] [ ] [ ] [ ]

Four (4) almost square- rectangles.....side by side....But....alas....NOT a " Beam on Beam " arrangement !! Not all four (4) beams....superimposed over one another !!
Hmmmm...." Twist and Shout "

I have an idea on how to do this....with two (2) NUBM044 and two (2) NUBM07E.....not easy....not inexpensive...but...maybe could be done ?????????? Maybe even in a Hand Held format....maybe not ???

Who is up for 20W "o" Blue....ALL in One beam.... Mooohahahaha !!! ( There will be a discount offered if you like " Zippy the Clown " !!!!! )

CDBEAM
 

diachi

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Logsquared beat me to it, but if you have an even number of beams (>2) then stacking them vertically and horizontally is the way to go, rather than just knife edging them on the horizontal axis.

It'd be like this (although a little wider on the horizontal axis or narrower on the vertical, for more of a square stack):

||
||

Versus this:

||||

You can see the effect quite clearly in this image (look at the first lens on the telescope at the left):



Alternatively, if you're using 4 LDs (or more) you can knife edge each set of two and then PBS the two sets of knife edged beams for an even smaller beam profile as the stacked beams can be superimposed on eachother. The image above is doing that, although on a larger scale.


An anamorphic prism pair is a good choice for correcting the fast axis on multiple stacked beams, no aberrations with those and easier to align IIRC. The trade-off being a lower magnification and higher losses. Works perfectly well on the lower power blue LDs at least (A140 etc), may not be enough magnification for the higher power blues.

 
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Hi Logsquared,

Thank you for interest in my project and help. Later I will also try the ---- setup. But I am still interested in finding how good a result can be achieved with KE like this I have now!

And I have a question: why are all cylindricals (I understand that both Dave from LSP and Mateusz from Optlasers produce them mostly for purpose of projector making) Plano-covcave/convex and not Biconcave/convex? If aberration is the result of high refraction angles of highly off-center beams but is almost not detectable with better centered beams, would not two smaller refractions on each BCC/CX result in smaller final aberration than one bigger on PCC/CX?

Am I wrong thinking that?

Diachi,
All anamorphic pairs I have seen consist of equal prisms - so it would solve my problem as 3x, maybe even 6x expander (if I could find 18-24mm big 2nd prism) but how would you make beams converge?
OK, I can put a converging lens after but I wanted to do a build as compact and with as little parts/many functions as possible:) Sorry, I am not a millionaire like Ironman doing his builds in movies.
With cylindricals converging vs. parallel can be achieved just by sliding. Maybe if the prisms are not equal, then they would work as converger at the same time as expander, but only with one focal point which cannot be changed except by changing prism geometry? Same with a converging lens after anamorphics?
 
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Oh, Bob,

What you think I have already half-done. I mean single beam from 4 Blue LDs.
Two 44s + 2 07s is a passed step - I could not reach what I expected from that combination. And it was not portable as you remember.

Now I am trying to combine 2 06s with 2 binned 08s but again not sure how high the losses will be at end and if the beam will finally reach 20+W.

I do not know if such a portable makes sence (too scary) but I am doing this device small enough to be installed and tested on a RC tank chassis first:evil:
 

BobMc

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I have an idea on how to do this....with two (2) NUBM044 and two (2) NUBM07E.....not easy....not inexpensive...but...maybe could be done ?????????? Maybe even in a Hand Held format....maybe not ???

Who is up for 20W "o" Blue....ALL in One beam.... Mooohahahaha !!! ( There will be a discount offered if you like " Zippy the Clown " !!!!! )

CDBEAM

I like "Zippy the Clown" :D

Sending pm :)

Edit; I can not tell I lie, does it count if I just googled who "Zippy the Clown" was. :tsk: :tsk: :tsk: :D
 
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CDBEAM777

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Oh, Bob,

What you think I have already half-done. I mean single beam from 4 Blue LDs.
Two 44s + 2 07s is a passed step - I could not reach what I expected from that combination. And it was not portable as you remember.

Now I am trying to combine 2 06s with 2 binned 08s but again not sure how high the losses will be at end and if the beam will finally reach 20+W.

I do not know if such a portable makes sence (too scary) but I am doing this device small enough to be installed and tested on a RC tank chassis first:evil:
Tank Chassis !!!! Yikes...MMMmmmm SOoooo...Don't forget the " Connex " HD Digital FPV system...and a pair of DJI 1080 DPI FPV googles....NOW...
" Lite'em UP "....

OK...yes....two 044's and two 07E......with that special Dichro....to combine....That is what I was thinking of !!!BUT...you did not hit 20W !!! ??? Hmmmm??

The raw output ( B4 optics) of the four (4) LD's could be about 22W...BUT... Well....that special Dichro must have a higher optical loss....not surprising !!! With the wavelength SO close together !! :scowl::scowl::scowl:

I am not experienced with this special B-B Dichro....just the standard RGB Dichro optics....which have a typical Transmission/Reflection efficiency of about 95%

And....I think the special Dichro mirror MAY demand a non-standard incidence angle as the beams enter the Dichro. So...non-standard means...NOT a 90 degree set-up....which means...takes a much greater space to set up !!:cryyy:

I am sure you have trialed MANY varied beam angles...to achieve maximum Transmission/Reflectivity with the B-B Dichro. Of course...there will be a certain angle alignment....where one achieves the best results....but....even using that optimal arrangement....it remains an optical reality....that you may have limited efficiency !! SOooooo...you loose power...maybe a lot of power ??? What PO did you reach ? I assume you were driving the 044's and the 07E at about 5A ?? What was your raw power before any optics ??

Optics are just a BITCH...Seems as though...the Universe is against us !!!
ALWAYS throwing a obstacle in our path !!!...

Good luck....PLEASE keep us posted on your experiments !!

CDBEAM
 
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No, the seller said that the optimal angle had to be 45° like with other Dichros.

Here is the picture of what I did and my overpec LPM showing 25W but I know it meant maximum 19W in reality if corrected.

http://laserpointerforums.com/f42/brightest-single-blue-beam-4-diodes-combined-99106.html

It could be that I happened to receive underspec 07s. Also the drivers were set at 4.5A and there were cylindricals at the end. So the losses added up all the beam path long... But I think that the main losses were on PBS cubes - they shined like crazy!

About tank gun develpoment I am going to open another thread in Optics section. I already encountered some difficulties with that project, too - the Universe is against us, you are right!

Let us keep this thread for OT (Lasertack set + Quad module holder).
 

paul1598419

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Still like what you've done with your optical bench, Light superglue. Yeah, the optics are going to be trial and error, but in the end you may have something reproducible for yourself and/or others here.
 

CDBEAM777

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Well...Been thinking about this....SO...We really do not know what your PO is !!

SO...if you drive both the NUBM044 and the NUBM07 at about 4.5 A....
Raw Optical power could be typical at a total of 23.5W....Now we run thru ALL the optics !!

I SPECULATE Optical losses as follows;

B-B Dichro @ 10% loss
Cylindrical's @ 3% loss
PBS Cubes @ 3% loss
Waveplate @ 2% loss
Bounce Mirror @ 2% loss
----------------------------

Total Optical loss ~ 20%

OK....So that is the price you pay...to get the " Beam-on Beam " geometry....Like a tip...All components do their job....and have a cost to extract from your initial raw PO @ 23.5W.....each component....." Wants a Tip " hahaha !!

SO....23.5 x .80 = 18.8 W

Hmmmm....looks like all is good...

The " Gods of Optics " are served !!! I would say the only way to break the 20W barrier....More current to the LD's....but....that may cost ya also !!!..in LD life...or a COD event....

But then...It is really unlikely our eyes can tell the difference between 18.8W vs 20W....
SO....Now...how to shoehorn all those components...into a Hand Held beauty !! It can be done !!!!......It WILL be done !! :eg::eg::eg:

CDBEAM
 
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BobMc

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Well...Been thinking about this....SO...We really do not know what your PO is !!

SO...if you drive both the NUBM044 and the NUBM07 at about 4.5 A....
Raw Optical power could be typical at a total of 23.5W....Now we run thru ALL the optics !!

I SPECULATE Optical losses as follows;

B-B Dichro @ 10% loss
Cylindrical's @ 3% loss
PBS Cubes @ 3% loss
Waveplate @ 2% loss
Bounce Mirror @ 2% loss
----------------------------

Total Optical loss ~ 20%

OK....So that is the price you pay...to get the " Beam-on Beam " geometry....Like a tip...All components do their job....and have a cost to extract from your initial raw PO @ 23.5W.....each component....." Wants a Tip " hahaha !!

SO....23.5 x .80 = 18.8 W

Hmmmm....looks like all is good...

The " Gods of Optics " are served !!! I would say the only way to break the 20W barrier....More current to the LD's....but....that may cost ya also !!!..in LD life...or a COD event....

But then...It is really unlikely our eyes can tell the difference between 18.8W vs 20W....
SO....Now...how to shoehorn all those components...into a Hand Held beauty !! It can be done !!!!......It WILL be done !! :eg::eg::eg:

CDBEAM
I am in your corner !!! GO CDBEAM777 GO!!! :D
 
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Yes CDBEAM et all., now you understand why I am trying to put on the beam(s) path as little obstacles as possible!!! Even if it may contradict to the common practices.

And could you please move the discussion of 20W single beam into this thread:

http://laserpointerforums.com/f49/n...-tank-gun-prototype-do-they-exist-100803.html

There I have an almost finished design of what you are talking about and this thread was to discuss knife-edging. They are two of my different projects with different purposes.
Yes, it was supposed to be a tank gun, not a tiny pointer but if you have a physical draw how to make it into a torch you are welcome!

What did engineers say of my OpenScad script/.stl file at the end? Is there any way to convert it into CAD/CAM tool path program?
 
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Now with Big 6x cylindricals from CDBEAM I have been doing more of the Knife-Edging & Converging experiments with four NUBM44.

All tests were done at 500mA current.
By using both of these lenses the length of the convergence spot was not improving compared to previous tests using 3x C-lenses from Optlasers. The 2 inner beams alone produced a short spot at 2m distance (pic.1 and 2), but all 4 beams – pretty long one (pic. 3).

But… after having tried many combinations of different C-lenses on the sliding guides I found that making a “biconcave” lens from two Optlaser´s 2x sets and using it with PCX from Big 6x set (pic. 4) resulted at the end in a spot only 6mm long (pic. 5).

More funny even was that contrarily to observed before, two out of center beams alone (pic. 6) gave in this setup shorter spot (pic. 7) than all four beams combined! What means that more centered beams are harder to focus here than the less centered ones...

And this device sets this white paper on fire at 2m distance already with 1.2A current...
 

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BobMc

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Now with Big 6x cylindricals from CDBEAM I have been doing more of the Knife-Edging & Converging experiments with four NUBM44.

All tests were done at 500mA current.
By using both of these lenses the length of the convergence spot was not improving compared to previous tests using 3x C-lenses from Optlasers. The 2 inner beams alone produced a short spot at 2m distance (pic.1 and 2), but all 4 beams – pretty long one (pic. 3).

But… after having tried many combinations of different C-lenses on the sliding guides I found that making a “biconcave” lens from two Optlaser´s 2x sets and using it with PCX from Big 6x set (pic. 4) resulted at the end in a spot only 6mm long (pic. 5).

More funny even was that contrarily to observed before, two out of center beams alone (pic. 6) gave in this setup shorter spot (pic. 7) than all four beams combined! What means that more centered beams are harder to focus here than the less centered ones...

And this device sets this white paper on fire at 2m distance already with 1.2A current...

Following your build closely. Enjoying every post/picture. Best wishes with your build. Can't wait to see the final product. :)

Curious about the more centered beams being harder to focus. I'm guessing they create a smaller dot on the mirror???
 

paul1598419

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Looks like you've come a long way since last I looked at these. I wonder how much power you'll end up with when this thing is finished. Very good information to impart to all of us here. + rep
 
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A little update on the project.

When time was available this summer I tried to fight the aberration.
Thinking that this aberration of external beams was the result of higher refraction angles with Optlasers/Bob lenses which have pretty short f (designed for short setups) and high curvature, for my experiments I purchased some cylindricals from Thorlabs, among them ones with f = 75mm and -12.7mm, so 6x expansion could be done with lens separation twice longer than on previous pictures (pic. 1).
I suggested that longer lens separation and lower curvatures would also mean lower refraction angles of beams and reduce aberration to some extent.

Well, the spot at 2m (500 mA) became a little (1-2mm) shorter than on setups I had before and paper sheet was igniting at 1A now and not at 1.2A like before (pic. 2). But this change was not drastic – a little more concentrated focus but still not square.

Now at 5m (here 1A current, pic. 3): it is clear to see that highly refracted out of center beams focuse closer than internal beams (sketch on pic.7). Here I show what the spots look like if the wall would be at different distances. Sorry for awkward hand righting.
Pic. 4 shows all 4 spots when they separate again after focus range (beam waist range).
On pic. 5 two internal spots focus and combine pretty well (on line marked f 2,3 on the sketch) but two external beams are already diverging after their focus line (marked as f 1,4 on the sketch).
On pic. 6 you can see the shortest combined spot of 4 all beams if the wall is between f 2,3 and f 1,4 lines. Spot dimensions ~10x5mm.

Another thought I had was that the beams may not be perfectly parallel, if so – this could be a reason for combining beams so badly alternative to aberration.
Indeed the micro size of all Lasertack mirror mounts makes it really tricky to align properly what may be not an issue at 2m distance, but comes into action at 5m+... But from what I know aberration must lead exactly to what I see here – outer beams focusing closer than internal beams!

Do you agree?
 

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