Any tips for knife-edging dual 445's...?

**Stuka** · 09-20-2011, 18:16

I'm considering combining a pair of 445nm diodes using a dual-diode knife-edge mount.
The mount holds the diodes in a side-by-side arrangement, with NO correction optics.

Can anyone offer any tips for diode orientation, beam alignment and knife-edge "trimming" that would provide a decent beam suitable for an RGB projector?
(Primarily for use as a "beam" projector, with some occasional graphics).

Thanks in advance!!

**ireedz** · 09-20-2011, 18:37

I just put together a couple quads using o-like lenses and what I did was stack them as close to each-other as possible. I get a good bit of smoke in the air and keep only the brightest center of the beam. It seemed to be the only way to get anything that would fit my mirrors at all. I'm getting a good bit of loss with my setup, but that was expected and eventually they will be replaced with cubed quads and different lenses. I think as long as you get the focus set well, that is the key. Let me know if you have any questions.

**taggalucci** · 09-20-2011, 19:23

Originally Posted by ireedz

It seemed to be the only way to get anything that would fit my mirrors at all.

Hi there

What size scanner mirrors are you using? I'm planning a quad blue using 4 side-by-side 445s with O-Likes.

**ireedz** · 09-20-2011, 19:34

Originally Posted by taggalucci

Hi there

What size scanner mirrors are you using? I'm planning a quad blue using 4 side-by-side 445s with O-Likes.

I have the DT-40 Wides with the standard mirrors. I don't recall the mirror dimensions. I think they are 5mm.

**swamidog** · 09-20-2011, 19:40

if you're planning on doing RGB graphics, i recommend you do something more than just knife edging. remember, the intent is to have all the far-field spots overlap as neatly as possible.

here's a little dual 445 unit i built. it mixes cleanly, has excellent divergence and has no problems fitting on my scanner (dt40w) mirrors.

dual-445-complete.jpg

dual-445-ap-09.jpg

dual-445-ap-08.jpg

Originally Posted by Stuka

I'm considering combining a pair of 445nm diodes using a dual-diode knife-edge mount.
The mount holds the diodes in a side-by-side arrangement, with NO correction optics.

Can anyone offer any tips for diode orientation, beam alignment and knife-edge "trimming" that would provide a decent beam suitable for an RGB projector?
(Primarily for use as a "beam" projector, with some occasional graphics).

Thanks in advance!!

**ireedz** · 09-20-2011, 20:10

Originally Posted by swamidog

if you're planning on doing RGB graphics, i recommend you do something more than just knife edging. remember, the intent is to have all the far-field spots overlap as neatly as possible.

here's a little dual 445 unit i built. it mixes cleanly, has excellent divergence and has no problems fitting on my scanner (dt40w) mirrors.

That looks quite nice. I'm not sure that Stuka would be happy with the beam that he will get from just knife edging either. I think not.

**Stuka** · 09-20-2011, 20:17

Originally Posted by swamidog

if you're planning on doing RGB graphics, i recommend you do something more than just knife edging. remember, the intent is to have all the far-field spots overlap as neatly as possible.

here's a little dual 445 unit i built. it mixes cleanly, has excellent divergence and has no problems fitting on my scanner (dt40w) mirrors.

dual-445-complete.jpg

dual-445-ap-09.jpg

dual-445-ap-08.jpg

Dang, that's a lot of optics - but the beam does look good!!!

Care to elaborate on the beam path, the optics you used, and where you got them?

**CDBEAM** · 09-20-2011, 20:19

Stuka... See attached pics....This is a experimental test set up I did to just experiment with knife edging in preparation for the Zod Quad. I would only use a PBS with a dual set up....like Swamidog's....NICE BEAM....no knife edging !! I cannot understand the beam shaping optics on the LD on the right....almost looks like cylinderical optics ??? or maybe Anamorphic Prisms turned 90 degree ???

Anyway.....I MUST use knife edging to do a quad !!! My test set up uses Daves LD mounts and Flexmounts. My name for it ( MUST name everything ) is the Zod Dual...mmm or Zuul.....Of Course !!!

I also do not understand why you would choose more optics loss by going thru two sets of beam shaping optics.....then go to combining ??? Perhaps SD can further explain his set up ?????But....his beam SURE looks great !!! That is for sure !!!

Like I said....this is just a set up to experiment....B4 I drill and tap many, many mounting holes in Copper !!!

Oh...And...Go with the JML PBS....I bet it is the best efficiency we are going to see !!!!! 97% efficiency on transmission and 95 % efficiency on reflectance !!!

And for the asphericals...go with the O Like and Simons Prisms for beam shaping...ALL My opinion....subject to change daily !!! haha

CDBEAM and Terrawatt

**swamidog** · 09-20-2011, 20:24

sure.. i'm using aixiz blue lenses and prisms/cube from the group buy p1t8ull did last year.

here's the render i made as a template before doing the physical construction.

dual-445-render.jpg

Originally Posted by Stuka

Dang, that's a lot of optics - but the beam does look good!!!

Care to elaborate on the beam path, the optics you used, and where you got them?

**Stuka** · 09-20-2011, 20:36

Cool - looks good!

Thanks!

**swamidog** · 09-20-2011, 20:38

cd, yes. i'm using two sets prism pairs. one diode is rotated H and one diode is rotated V so you have to rotate the prism pairs as well.

i'm using this system in my rgb rig. these diodes are so crazy powerful that i don't care about losses. the intent was to get the best beam that i possibly could without resorting to fiber.

Originally Posted by CDBEAM

Stuka... See attached pics....This is a experimental test set up I did to just experiment with knife edging in preparation for the Zod Quad. I would only use a PBS with a dual set up....like Swamidog's....NICE BEAM....no knife edging !! I cannot understand the beam shaping optics on the LD on the right....almost looks like cylinderical optics ??? or maybe Anamorphic Prisms turned 90 degree ???

Anyway.....I MUST use knife edging to do a quad !!! My test set up uses Daves LD mounts and Flexmounts. My name for it ( MUST name everything ) is the Zod Dual...mmm or Zuul.....Of Course !!!

I also do not understand why you would choose more optics loss by going thru two sets of beam shaping optics.....then go to combining ??? Perhaps SD can further explain his set up ?????But....his beam SURE looks great !!! That is for sure !!!

Like I said....this is just a set up to experiment....B4 I drill and tap many, many mounting holes in Copper !!!

Oh...And...Go with the JML PBS....I bet it is the best efficiency we are going to see !!!!! 97% efficiency on transmission and 95 % efficiency on reflectance !!!

And for the asphericals...go with the O Like and Simons Prisms for beam shaping...ALL My opinion....subject to change daily !!! haha

CDBEAM and Terrawatt

**CDBEAM** · 09-20-2011, 20:42

Thanx SD....Yes...The first set of Anamorphics are rotated 90 deg....as they would need to be....but...NOT to argue with a GREAT beam.....I dunno ??? Maybe the prisms work better when each beam is shaped first...THEN combined....I must think about this...Perhaps THIS IS the way to go....A while back....someone used two sets of prisms....on only one beam.....one set at 90 degree to the other. I have NEVER seen THIS set up B4....but...BOY....that beam dot looks good !!!

CDBEAM

OK...Did some Thinking....Ouch ... How about put one LD output thru a wave plate....that would allow for combining...and keep both axis in the same orientation....so the Anamorphics ( One Set ) could do their beam shaping ?? Optics loss may be the same ????? still going thru three optics....And yes !!! The best beam shape
trumps everything else....I know we have had the wave plate, PBS then Prism set up done....I wonder which one
outputs a better beam for a dual LD set up ???????????????????????????

**swamidog** · 09-20-2011, 20:46

that spot is at 40'. the scorch marks on my wall attest to the energy density.

Originally Posted by CDBEAM

Thanx SD....Yes...The first set of Anamorphics are rotated 90 deg....as they would need to be....but...NOT to argue with a GREAT beam.....I dunno ??? Maybe the prisms work better when each beam is shaped first...THEN combined....I must think about this...Perhaps THIS IS the way to go....A while back....someone used two sets of prisms....on only one beam.....one set at 90 degree to the other. I have NEVER seen THIS set up B4....but...BOY....that beam dot looks good !!!

CDBEAM

**CDBEAM** · 09-20-2011, 21:28

SD.....Your beam dot looks almost round ??? Rotating a set of A Prisms MUST be a real PITA.....Anyway.....My quest is mainly lies in the best beam geometry for a quad set up.....and my experiments are meant to educate myself on the mechanics of that area !! I would be VERY curious as to what dual set up gives the BEST geometry....and yours looks VERY good !!!

Anyone else have any insight ???????????????????????

CEBEAM

**LaNeK779** · 09-21-2011, 01:58

here is another interesting idea http://www.photonlexicon.com/forums/...t=beam+folding

i think it is the best (but most fussy) solution

**CDBEAM** · 09-21-2011, 14:58

OK then...I did a little sketch....my question is.....which set-up would deliver the best beam qeometry ...for a dual 445...Swamidog or the Zuul ??? SD's produces a great beam...no doubt !! But has anyone tried a concept like the design attached ??? if so.....what beam geometry at 30M....and what beam geometry at 30M for the SD design. Why 30M you say ??? Just a number which I think represents the farther limit of what most at PL would be interested in.

All this is to answer Stuka question.....What is the best known current design for a dual 445 set-up ?? ...Dual sets of Anamorphic Prisms, then into a PBS....or.....One 445 LD into the PBS, the second 445 LD thru a waveplate to rotate the polarization...then on into the PBS.

As of now....I would say that a dual does not need knife edging for sure...SD's design is the best I have seen for beam geometry....but I still wonder if that is the optimal. Yikes....I know Marc ( CT)...." How many coherent photons are on the head of a pin ? " hahaha
CDBEAM

**swamidog** · 09-21-2011, 15:10

your design will give you either a "_" or "=" shaped spot depending on the height relation of your diodes. mine gives a "+" that fuzzes into a round looking spot. the spot photo i posted is at 40'. that's the longest run available in my house.

Originally Posted by CDBEAM

OK then...I did a little sketch....my question is.....which set-up would deliver the best beam qeometry ...for a dual 445...Swamidog or the Zuul ??? SD's produces a great beam...no doubt !! But has anyone tried a concept like the design attached ??? if so.....what beam geometry at 30M....and what beam geometry at 30M for the SD design. Why 30M you say ??? Just a number which I think represents the farther limit of what most at PL would be interested in.

All this is to answer Stuka question.....What is the best known current design for a dual 445 set-up ?? ...Dual sets of Anamorphic Prisms, then into a PBS....or.....One 445 LD into the PBS, the second 445 LD thru a waveplate to rotate the polarization...then on into the PBS.

CDBEAM

**CDBEAM** · 09-21-2011, 15:38

Well...I am confused ( A normal state )...at 40' ( slightly over 12M )....a single 445 LD , with O-Like collimator, going thru a set of P1t8ull's prisms produces a ( VERY close to ) 14mm square. I have done this set up. By taking another 445 LD and passing thru a waveplate....one square is overlaid via the PBS on top of the other.

Even if the square is slightly a rectangle...a very slight rectangle....then you would be comparing a fat plus shape that at 40' that looks like a circle.....to an almost square rectangle. I guess it them comes down to energy density/square mm vs. the geometry that most closely approaches a circle. I would speculate ( read quess ) that the Zuul would have just a bit more energy density....BUT the SD would look just more slightly like a circle. " Pay ya money...Takes ya pick " !!

I dunno...just speculation ??? Likely at 40 feet...nobody could tell the difference.....and only the photonic obsessed would give a Rat's Ass.

CDBEAM

**LaNeK779** · 09-21-2011, 15:45

i still think that the beam folding method produces the best results, especially if you are prepared to dive into pbs and waveplates anyway

**CDBEAM** · 09-21-2011, 15:55

I would like to see a set-up of the beam folding !!! My mirrors are optically ground on the edge....but I question the abillity of the knife edge to slice the slow axis in half...and feed it back into itself ??? It seems that you can only get SO close to the edge...then the spill over losses start to suck !!! Hey...What do I know ????? Perhaps the optical grades we experiment with have their limitations....and components costing 25X do much better ????

CDBEAM

**swamidog** · 09-21-2011, 15:57

not sure what lens you used. sharply focused at 40' and through a prism pair, i get a very thin line maybe 12mmX3mm. if you're getting at 14mm square, it sounds you might be having a focus problem.

Originally Posted by CDBEAM

Well...I am confused ( A normal state )...at 40' ( slightly over 12M )....a single 445 LD , with O-Like collimator, going thru a set of P1t8ull's prisms produces a ( VERY close to ) 14mm square. I have done this set up. By taking another 445 LD and passing thru a waveplate....one square is overlaid via the PBS on top of the other.

Even if the square is slightly a rectangle...a very slight rectangle....then you would be comparing a fat plus shape that at 40' that looks like a circle.....to an almost square rectangle. I guess it them comes down to energy density/square mm vs. the geometry that most closely approaches a circle. I would speculate ( read quess ) that the Zuul would have just a bit more energy density....BUT the SD would look just more slightly like a circle. " Pay ya money...Takes ya pick " !!

I dunno...just speculation ??? Likely at 40 feet...nobody could tell the difference.....and only the photonic obsessed would give a Rat's Ass.

CDBEAM

**CDBEAM** · 09-21-2011, 16:18

Yikes squared !!! SD...you said you are using...."aixiz blue lenses and prisms/cube from the group buy p1t8ull did last year".
OK...3mm at 40 feet ???????. 12mm x 3mm ??? where is the FA magnification from the prisms ??? Anyone else who really understands optics....please jump in here....for I am clearly confused....and perhaps out of focus too !!

CDBEAM

Another question...I assume your beam pic is the geometry at 40 feet ????????? I do not understand !!! That beam geometry....while a great looking circle....is approx 40mm in diameter....when compared to the wall plug plate just to the right of the spot...and is at the same termination plane distance. ??? What am I missing here ???

Yikes again....I am looking at your front prism.....on the normally placed set.....an it does not look like the normal " Zoof Templete "...??? Just trying to understand optics....my most challenging area !!!

**jooopy** · 09-23-2011, 15:57

Originally Posted by swamidog

your design will give you either a "_" or "=" shaped spot depending on the height relation of your diodes. mine gives a "+" that fuzzes into a round looking spot. the spot photo i posted is at 40'. that's the longest run available in my house.

Hey Swami... whats the measurement of the beam spot here at 40feet? 3x3mm aperature right? what like 15x15 this wall dot? 14x3 would bewithout your prisms or did I misunderstand? Yes I'm confused on the explanation as soo many #'s flew around here.~jimmy

**cybertoyz** · 09-23-2011, 17:15

Where did you purchase your PBS? I am not familiar with JML
Thank YOU

**CDBEAM** · 09-23-2011, 19:36

CToyz...JML is in Rochester NY. They are very pleasant to deal with. See: www.jml@jmloptical.com

under beam splitter, part # CPO21361 @ $ 105.00 Not cheap....but 98% transmission and 95% reflectance. Perhaps there is better

out there....at several times the cost ??? Dunno. Perfect for 445nm beam combining and it looks coated.

CDBEAM

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