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The Green Gargoyle 10.08 W @ 520nm

CDBEAM777

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Hahaha....You guys are more " Mad Scientists "....than I am....BOO HAHAHAHA !!! I am still waiting for our more technical members to chime in here !!!......Cricket sound...Cricket sound...Cricket sound !!!...….What if..... we are as expert as it will get ???? Oh Crap !!!

RC...I like your set up...NOW....just couple that idea...with an IR target range finder....to determine the distance to the Far Field you have selected...
So, so....IR tracking determines the distance, feeds this telemetry to micro servo adjusters....which adjust the LD beam Pitch/Yaw to align at the target plane....HAHAHA....simple....Eeeeehh...Maybe not !!! dArpa tried it....keeping alignment in the battlefield drove'em nuts !!!....HAHAHA....Short Trip !!

I suppose...time to call THOR LABS Technical support.....Make up some story as to why....I am SOOoooo technical challenged !!! ….Hmmmm ... Some casual mention of " The Accident in the Lab " I am sure they would get a laugh or two !! ….." As though his Ape's brain could contain the secrets of the Krell " !!!! CDB
 
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CurtisOliver

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Another great project. I’m also looking forward to seeing the progress and completion. :)
 

CDBEAM777

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Another great project. I’m also looking forward to seeing the progress and completion. :)
Completion....Completion you say....Whatz That ????….Oh yea....were ya finish a build....I got three (3) builds about to cross the finish line....errr….ah..
Christmas is coming !!

Some builds just never get off the ground. Sorry Boyz….Sometimes technology renders a build OBSOLETE !!...It just never gets started or never gets done because new technology has delivered a superior or less costly render !! I have had more than one (1) build end up in this " FTL " ( Failure to Launch ) bin. Sometimes, the cost is just too high.. Getting a 3K (Just parts ) project funded....hmmm....a challenge for me ( Not for Plantars !!)

LPF is and should be a germination area for new ideas. We should and do share. Both success....and failure ! I will continue to generate ideas.
Maybe some grow frustrated at the eventual lack of completion...I know I do....But....that is just the way it goes. This is....after all....a hobby....NOT a business. The core value of LPF remains the sharing !! I need a rich Uncle !!

My only other option....build two (2)…..and sell one to fund the other. Whatever ?? $ 508.00 for one lens...Yikes.....I still like the idea of
" Rent to Own "....Too bad the Projector manufacture do not share design's....but....why would they ???? Thousands of research $$ are spent to develop product....so I can understand why they would never share.....Meanwhile, we do share...even silly ideas !!

CDB
 
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steve001

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What I like about an anamorphic prism pair is the adjustability for different amounts of correction, you guys put together the idea lining up the outputs of several diodes into one:



I had not heard of the Axicon lens before, very interesting, but how do you keep the ring from expanding as the light travels forward?


A good question. But this type lens has no practical application for creating low diverging laser beams by themselves. Your idea of creating a low diverging circular is interesting.
 
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Alaskan

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Collimate the beam, then expand one side using cylinder pairs to square up the beam for even lower divergence than the collimation lens alone can produce for the fast axis.
 
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logsquared

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Prism correction is nice especially the amount of space they take compared to most cyl set-ups.. They have some drawbacks though. Usually higher optical losses. Plus they have the same "issues" as cyl lens correction when trying to correct multiple knifed beams. If you try to overlap the far-fields of multiple beams before the prism correction, the near field after the prisms get spread apart proportional to the magnification. So you end up with IIII in and I I I I out. Big gaps.

Axicons look like fun to "play" with. I might try and make some from acrylic on my lathe and see if they can be polished enough for playing "testing" with.
 

steve001

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Collimate the beam, then expand one side using cylinder pairs to square up the beam for even lower divergence than the collimation lens alone can produce for the fast axis.
I think you should experiment to see if this idea works.
 

Alaskan

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OK Case Opened:

Anamorphic prisms are used to change the dimension of a beam in one axis, the effect being analogous to that of a cylindrical lens. Beam expansion is beam expansion with reduced divergence in that axis.

Edit:

Read this: https://photonlexicon.com/forums/showthread.php/18839-Beam-Astigmatism-Correction-Anamorphic-Prism-Pair-Theory-Gaussian-Beams-Dispersion

Snip:

"what is neat about prisms is they stretch your beam without focusing it, so there there are none of the abberations associated with cylindrical lenses! Thorlabs has some good explanations on how this works, along with plots of typical angles see the 'beam expansion' tab at http://www.thorlabs.com/newgrouppage...ctgroup_id=149"
See the www.lasertack.com advertisment for their ebay prism pair listing:


Anamorphic prisms are used to expand one beam axis while keeping the other unchanged.

High power laser diode like 405nm, 445nm, 520nm or 638nm have a high divergent axis. In far field it gives an asymmetrical beam profile and excludes these laser diodes from many applications like show lasers etc.

Using our anamorphic prisms allows to reduce the far field beam divergence dramatically.

Example
  • 3.5W 465nm laser diode
  • beam size = 4x1mm
  • Divergence = <1mrad by 5mrad
By expanding the 1mm axis to 4mm the divergence is reduced by factor 4. After beam shaping you get a beam of 4x4mm and a divergence of 1.25mrad at full angle.



Case Closed :)
 
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CDBEAM777

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My head hutrz ! SO...so....LS you say ...Anamorphic prism have the SAME issue with Multiple Knife edge....well...that is NO GOOD....seems that individual C-Lenses will be demanded...PRIOR to knife edging...." Bhuler….Bhuler….Bhuler ".... ANYBODY !! Lightsuperglue….you have been experimenting with Knife Edging 044's...What say you ????
I know LS knows his Stuff !!!!!!!!!! So....He likely speaks from experience....TO BAD !!!.... I had hopes a set of AP would suffice....Crap !!

Maybe some surplus gizmo has one of these Axicon lenses....for cheap….just to experiment with ??? Maybe Kvant, Edison, Aten, Opt or X-Laser has experimented....Hmmmm ??? Dunno !! Maybe Too costly.....or....Just does NOT work....Or has too critical alignment demands....dunno ??? Just throw'in darts here !!!

I remember....back about when LPF was formed....there was some discussion about Axicon lenses.....seem to remember no practical build....or maybe....just no follow thru ????.....I will do some WWW surfing.

Fun, Fun !

CDB
 

CDBEAM777

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Hmmmm...for 20 bucks....I could tinker with this !!


I just bet the perfect alignment of eight (8) beams ….is just TOO much of a PITA !!!.....But then....aligning Eight (8) knife edge units is No... walk in da Park !! Hmmmmm….The Special LD mount WITH Pitch adjustment MAY have application here. I think Thantung machined one.....will locate my old drawings ! CDB

Added: Found the thread from last year...


This was my design....Somebody did machine one....IIRC....it was Thantung.....Perhaps a "Pitch adjustable mount" could be used in conjunction with a single Axicon Lens....Still just throw'in out ideas !!! Hmmmm I imagine….where the beam strikes the Axicon Optic ….and the Incidence angle of the beam axis would determine Beam-to-beam separation and parallel condition !!….

Then again....perhaps....the Round surface of the Axicon geometry..... screws everything up ….and the beams are spread out...as they are combined....OK... Who knows ?? CDB
 

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Light superglue

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Hi Bob,

What was the last pic. supposed to be, it is too small too see at 6.2 kB.

Axicons and prisms may be fine for someone who has all mounts for them ready, but I keep with cylindricals because mounts and parts I have at home are for cylindricals. Even if a pair cost 55usd from LSP.

BTW how is it going with C-lenses GB2? Can this manufacturer do custom microcylindricals (3mm wide and long)?

I have been liking the axicon idea for years but yes it would need a Death Star design like on pic. from Alaskan - so no way for me to use NIchia blocks readily available on ebay with (to some extent) parallel beams.

From a lot of knife egding experiments I draw a conclusion that the strongest beam comes from 2x2 combining (with vertical offset) , not 4 in a row (IIII) because trying to correct it later will result in aberration. Or in case beams are corrected before KE, then if you want to add beam expander at the end, lenses in it would need to be aspheric what might be expensive...
 

CDBEAM777

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Hi Vladimir...Thanx for the knowledge from your experiments...Every bit if added information guides the GG design...SO...2 x 2 is the way t go !! Make a sketch please !!! I do better with pictures ...Thanx !!

GB for C-Lenses....stalled for not enough quantity yet !! IF I do the GG build...I will need 8 more !!!

Pic on last post was a LD holder....which has Pitch adjustability !! Maybe be demanded for use with an Axicon Lens !! Dunno ????


HMMMM....I bet....even with Axicon Combination….IF that even works....Each LD will need C-Lens correction....then all eight (8) feed into the Axicon

I dunno.....The Axicon looks neat....and may work....but....I am leaning toward the standard Knife Edge.....UNLESS.....UNLESS....I can get ALL eight (8) beams....to the Beam-on-Beam state....all Co-Linear !!...NOT side by side / Parallel....BUT....ALL on the same Ray Trace !!!....Which would need an Axicon Lens....Not an Axicon Mirror.

Anyway....Fun, Fun.....Thanx !

Bob
 

logsquared

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I dunno.....The Axicon looks neat....and may work....but....I am leaning toward the standard Knife Edge.....UNLESS.....UNLESS....I can get ALL eight (8) beams....to the Beam-on-Beam state....all Co-Linear !!...NOT side by side / Parallel....BUT....ALL on the same Ray Trace !!!....Which would need an Axicon Lens....Not an Axicon Mirror.

Bob
Sadly, I think getting all the beams co-linear and overlapped violates the laws of the universe:(

I'm really intrigued by the axicons. I've been thinking about them since you posted about them the other day. At first they confused the crap out of me. It was really hard for me to visualize how the beam would react to the flat prism in the (radial) axis and the curved circumferential surface. Yesterday I poured the basement floor in a house I'm building. Today I realized I'm not as young or in shape as I thought I was:) So after cutting the control joints in the slab this morning I've been recovering on the couch all afternoon. I really put some thought into it sitting here and think I finally have a grasp on it..... Maybe

I think using one axicon and aiming multiple lasers at it (deathstar approach) has no chance of working. The circumferential curvature will distort the individual incoming beam when it exits. Each beam will probably have a semi-circular or crescent shaped output.

Using two series axicons in a beam expander type set-up has more of chance of grouping all the beams together. Using the parallel multi-beam input like Alaskan drew up should group all the beams together on the output. Here is the problem (I think). If we think in terms of the optical invariant the diameter in the radial axis of the input beam will be the same width after the series axicons (in that axis only). So, the divergence will stay them same. But in the circumferential axis the beam gets reduced by the ratio of the input to output ring diameter (two axicons in series produce a collimated ring from an input beam). So lets just say the ratio is 20 and the input beam has a divergence of 1 then the output beam will have a divergence of 20 (in that axis). Also, using Alaskans drawing as reference, all the space between beams is wasted. This is because the output "ring" of beams will still have these gaps, just shrunk down by the "ring" ratio and also gain divergence in that axis.
 

CDBEAM777

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LS...Just reading of all your work....made me tired !!! Knock it Off !! Your last paragraph ….did catch my hair on fire !! I think I understood....oh....maybe 75% hahaha !!

OK...in post #26....I also had a passing thought as to the issue with the conicity of the Axicon lens as regards to distortion !! Hmmmm ??….Even without this problem....alignment of the individual LD beam axis would just be....er...challenging !!

And.....If No Co-linear Beam-On-Beam condition can be attained....well....screw it....hardware for Knife edge exists....and I know how to work with that !!!! Light superglue..I must find your thread....where you did your latest combining...IIRC....there were lotsa pics !! Thanx guys !! Bob
 

CDBEAM777

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Thanx !! ...And....If we reverse the Ray Trace of the bottom drawing ??? What do we get ?????? Is there symmetry in direction ????

I likely have a misconception of some fundamental Optical understanding !!! But then...I am no Optical Engineer....Justa Hack !!! Look'in for a simple solution !! Can't blame a guy for trying !!!

CDB
 




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