Mega RGB via KTP / Dye / 445... Discuss...

[dsli_jon]

Hey there Cap...

Just found this thread - thanks Jon. I posted a photo of my deck mounted LS dye system at least a couple years ago?

Right on... thanks for the 'inspiration'... Yes, and 'DjStickyFingers' had it posted to his 'flickr' pages, 'as-if' it were his own werk, until I posted a comment on his page, there, giving credit where the credit was-due... http://www.flickr.com/photos/prodjal...7624242336736/

The only thing I 'hate' more than an illegally-operating 'hack' is an image-thief... If a Co. / proposing-to-be Co. is-really 'all-that' (they claim) 'awesome', etc...then why the frack would they *ever* need to post someone else's pix / werk, save-for 'reference' / historical-mention, etc...

OK, rant over...

BTW I still have a few dye modules and KTP lasers for sale if anyone is interested.

PLEASE, for the love of God, DON'T sell to that 'kid' or anyone w/o solid Class IV-experience, unless you're gonna personally train them... then,

...and it's not that I'm trying to 'tell you what you do' - I know you certainly need no 'guidance' from lil' ol me... just that with the 'cheapness' of these things, now, and the enormous-lack of 'education' / laser-safety knowledge / responsability-awareness, in-general, these-days....the 'rockets need fins', now, more than-ever...

Three-cheers for PL.... and You.
cheers...
j

PS - just saw the pic of your 'internals'... Brilliant, m8... ...just watch our fer 'ol StickyFingers', tho... ;D

[Photonbeam]

Hey there Cap...



Right on... thanks for the 'inspiration'... Yes, and 'DjStickyFingers' had it posted to his 'flickr' pages, 'as-if' it were his own werk, until I posted a comment on his page, there, giving credit where the credit was-due... http://www.flickr.com/photos/prodjal...7624242336736/

The only thing I 'hate' more than an illegally-operating 'hack' is an image-thief... If a Co. / proposing-to-be Co. is-really 'all-that' (they claim) 'awesome', etc...then why the frack would they *ever* need to post someone else's pix / werk, save-for 'reference' / historical-mention, etc...

Whoa! That sux! This is why some of us hesitate sharing photos and ideas with the PL forum.

[dsli_jon]

Whoa! That sux! This is why some of us hesitate sharing photos and ideas with the PL forum.

Yeah, well, I think, as some say, 'natural-selection' eventually takes-care of most of the 'weeds' around-here, and most-everyone else is pretty 'respectful', in that-regard... So, I wouldn't 'hold back' on-account of a few doofussees ... Though, I have-felt the 'need' to plaster any of our show / ref-pix, posted, with a 'DSLI-watermark', which, outside of a 'commercial / sales-context' is kinda obnoxious.... but, ya gotta 'protect' yer IP / werk, these-days...
...but, feel-free to hereby 'spank' DjClepto, there, all ya want...

Thanks fer sharing yer pix...
cheers...
j

[goninanbl00d]

Whoa! That sux! This is why some of us hesitate sharing photos and ideas with the PL forum.

Interesting that you should post those pics again, they just so happened to be the first pics of a dye laser system I ever saw.

I'm guessing it wasn't the easiest task in the world to move everything from the 630 over to the KTP532's optical deck? Nonetheless, very well done mod.

Also, just another question out there- does this dye module have any provision for tuning (BRF, diffraction grating, prism set) at all? From the pics I've seen I don't think there's a tuning mechanism, or provision for tuning at all. Not that I'd see it being used at all, PDT does rely on a fixed wavelength.

I.E. in this pic(which I believe belongs to Photonbeam dsli_jon):



The pump beam enters from the top, hitting first a focusing lens, then the fold mirror which directs it at the dye cell. (gotta love that yellow). Following the dye cell there's an intracavity optic (what I suspect to be a BRF, but it could be a Brewster plate or etalon (what do those do again?), for all I know). Following that there's what I'm assuming to be the output coupler mount, followed by the focusing lens for fibre coupling.

Everything I just said probably sounded like (and is) a bunch of garbage. I don't know, I'm just having a stab in the dark at it from the pathetically small amount of knowledge I have.

In another pic, presumably actually taken by ProDJAllen:



Said "BRF/Etalon/Brewster Plate" is now on a round mount. I'm guessing the fold mirror is dichroic (as it seems to get in the way of the red intracavity beam- cutting off part of the OC)? Either that, or maybe he's got it set up wrong.

Anyway, it's late, and I'm bored, so I might as well try to learn something.

And before I disappear into the night again, a question about the Laserscope's cavity design. From what I've seen, the KTP oven is adjacent to the YAG chamber, and between the YAG chamber and the Q-switch. From what I've read (once again, very little, but resources are few and far between), though, shouldn't the doubler be on the other arm of the Z-fold, as opposed to being on the same arm as the YAG? I guess in this case, the Z-fold is purely there to extend cavity length (as opposed to work black magic regarding keeping the 1064 and 2nd harmonic separate).

Gah, I'd ask more questions or for photos, but I'm still not sure I'd get eaten alive after whatever happened with ProDJAllen.

[dsli_jon]

Hey Mr G -

Also, just another question out there- does this dye module have any provision for tuning (BRF, diffraction grating, prism set) at all?

Yes, well, *ahem* in my pic, there you can see the BRF, in it's little cylinder-mount, and yes - you can 'tune' the output, quite-well.... fascinating little laser, this...

I'm guessing the fold mirror is dichroic (as it seems to get in the way of the red intracavity beam- cutting off part of the OC)?

Nope it clears the beam... this should 'clear things up' a bit...

Gah, I'd ask more questions or for photos, but I'm still not sure I'd get eaten alive after whatever happened with ProDJAllen.

No way, man, ask all you want! That's why we're *all* here, to learn... I learned some great stuff from you, in this thread, so
And "DJA" made his 'own bed', here, by lying and manipulating the entire community, so I don't think you really have anything to worry about....

...your name *is* goninanbl00d, isn't it?? jk..

cheers
j

[goninanbl00d]

Hey Mr G -



Yes, well, *ahem* in my pic, there you can see the BRF, in it's little cylinder-mount, and yes - you can 'tune' the output, quite-well.... fascinating little laser, this...



Nope it clears the beam... this should 'clear things up' a bit...





No way, man, ask all you want! That's why we're *all* here, to learn... I learned some great stuff from you, in this thread, so
And "DJA" made his 'own bed', here, by lying and manipulating the entire community, so I don't think you really have anything to worry about....

...your name *is* goninanbl00d, isn't it?? jk..

cheers
j

Yeah, that pic does clear it up- just that "Pro" *snicker snicker* DJAllen's pic seems to have his fold mirror in the way of the HR. Perhaps it's a "normal" fail, just like his milky-green DI water filter.

Either way I never expected the BRF to exist in the first place, let alone the cavity being tunable. I guess it'd make sense for it to be there, to 'pick out' 630nm instead of having it lase broadband (and potentially having power go to waste).

(Digression: I wonder if you had a ring dye running Pyromethene 597 or Rhodamine B, you could start a show at one end of the spectrum, and 'walk' through the spectrum as the show goes on. It wouldn't be noticeable at first, but someone ought to notice what once started as a yellow beam is now red as the show comes to an end. It probably isn't practical, but just some fudz for thought.)

In another pic by Allen:



The fold mirror is in the way of the HR- another case of "OOPS I b0RKED IT?!?!?", perhaps?

Also, why is there what appears to be an air bubble in the dye pipe? Surely that isn't supposed to be there? And you wonder how his lasers still work.

Anyway. So if I've got everything correctly, it more or less looks like this:



(and to think I always thought it was an end-pumped setup, I never really noticed the position of the fold mirror).

Now, coming back from the massive threadjack (this started out about a 30W RGB, remember?), I did a bit of thinking about it, and came up with this.



(I've thinned a lot of it down, so hopefully it isn't too stupidly confusing or hard to understand, and also why crucial cavity components are missing from the Laserscope KTP532 cavity )

So, of course, you start off with the all-important KTP532 cavity. For the purposes of my calculations I'm assuming it's doing more or less 40W stable, which is more or less average-high for this class of laser. It could be better, yet it *could* be worse.

With a 75/25 beamsplitter (yeah, it says 70/30 in the diagram, oops), you let 10W through, and pass 30W over to the dye cell.

Once again, assuming the dye cell is capable of running at 32-35% efficiency, you more or less get 10W of red out.

The red is first combined with the blue to give magenta, which is then combined with the green to give white, which is then passed to the scanning galvos, which make pwetty beams out of these insane amounts of power.

As for the blanking- oooh, fun tiem. Using the polarising filter (can't remember it's exact name), it'd be possible to vary the power of the output beam by rotating said polarising filter in the beampath. Mount that to a set of galvos, and you (in effect) have very, very fast analog modulation. It'd be easier than the AOM, if it works.

This theory may or may not work, I may be wrong. But if it did work, it'd be cheaper and less likely to blow up than an AOM.

That's also what the intracavity Brewster plate in the dye cell is for, to give a polarised output.

I figured since this thread is somewhat alive I'd give it a kick in the guts and try to bring it back to life. Enjoy the diagram. Or not.


Cheers,

Andrew

[dsli_jon]

Hey Sir A -

just that "Pro" *snicker snicker* DJAllen's pic seems to have his fold mirror in the way of the HR. Perhaps it's a "normal" fail, just like his milky-green DI water filter....

The fold mirror is in the way of the HR- another case of "OOPS I b0RKED IT?!?!?", perhaps?

Might-be, in his-case, dunno but on the other-hand, the beam, at the HR is *tiny*...

Either way I never expected the BRF to exist in the first place, let alone the cavity being tunable.

yeah, it's just that whole 'tissue-response' thing, and since the things were spec'd for 3W for the 'standard' module, and 7W for the 'hi-power' (...heh, there's some 'marketing spin' for ya... they were spec'ing @ 630nm, so I think it was 'expected' to toss some power, and still be plenty-ok...

(Digression: It wouldn't be noticeable at first, but someone ought to notice what once started as a yellow beam is now red as the show comes to an end. It probably isn't practical, but just some fudz for thought.)

Indeed, yellow sine-waves and/or beam-cones are especially yummy...

Also, why is there what appears to be an air bubble in the dye pipe? Surely that isn't supposed to be there?

I have seen them both ways... at-rest, they can have some 'air in the line' but that may-also be an indication of a 'vacuum leak' somewhere... others I have seen, have zero 'bubbles', at-rest... I think that would only cause 'troubles' if there were air-bubbles while running (would bunk-up the lasing-process...) and / or if it was actually leaking dye, somewhere...

Anyway. So if I've got everything correctly, it more or less looks like this:

Nice drawing...you're hired! And you're *very close* but the KTP-beam does pass-thru the dye-cell, and 'terminate' in a little 'pocket' in the BRF-mount....

Now, coming back from the massive threadjack (this started out about a 30W RGB, remember?), I did a bit of thinking about it, and came up with this.

Again, very nice.... Interesting concept....

Once again, assuming the dye cell is capable of running at 32-35% efficiency, you more or less get 10W of red out.

Running 'on-deck' like this, (no loss thru fiber) and 'fresh' dye mix, you could probably expect closer to 40% or-better... I have it on 'good authority' that LS, when 'proving' these things, *consistently* achived average-powers of 17+ WATTS of Red (!!!) And our own Dear Doctor Photonbeam achieved 15+ with his-design...But, certainly, yes, 'erring on the side of conservativism' is a good-idea...

Still, if you used a 'hi-power' KTP sys, that was giving you 55+ W, (on a really good-day... you could - in-theory - pump with ~45W of 532 and get 15+ W of Red...and still have 10+ W of Green to stand on it's own... I'd, personally, go with as much Red and Blue (15+ W, also.. maybe even 20W of Blue...) as-possible, cause even 8-9W of 532 is gonna be visibly 'monster' vs the R/B %, here...

As for the blanking- oooh, fun tiem. Using the polarising filter (can't remember it's exact name), it'd be possible to vary the power of the output beam by rotating said polarising filter in the beampath. Mount that to a set of galvos, and you (in effect) have very, very fast analog modulation. It'd be easier than the AOM, if it works.

A "1/4-wave plate" is what is used to attenuate, and it works in a 'perpendicular' direction to the beam-path, so, it wouldn't really work, the way you are thinking.. (but 2 points for creativity... Even if you used a 'dichro' to 'blank' the way you are thinking, the 'range of travel' to blank-completely is very-large (...and thus, much slower) than 'retro-style' blanking...

If 'djCartBeforeHorse', there was not 'lurking' as a guest, as I'm sure he is, I'd gladly share a pic of this 'retro-style' blanking, specifically-designed for larger-beams, like this (hint: it's *not* the 'classic paddle-style'... ) Once I know he has his Variance-app FILED and an acc.#, maybe I'll post it.. PM's, only, till-then...

And, too, I think you'd end-up wanting to throw yourself off a bridge, trying to 'sync' 2x paddle-style blanking-setups + analog-direct w/ the blues... Best to 'mechanically' blank them all for intensity, and do 'color-mixing' via a (relatively) hi-speed dichro 'color-box'.. Again, since this would never really be 'intended' for graphics, I think even the 'sin' of this relatively 'crude-approach' would be forgiven in the face of some sort of result, like this: (pic not ours...don't even remember where I found it, otherwise, I'd post credit...)

(...don't even-know if this is *real*... but sure looks-good..

Anyhoo, this is all a bit of 'fantasy football', right now... But certainly, keep posting your ideas and thoughts and *never* be hesitant to ask... I can only hope that my 'Elders' like Pat and Sir Janders, there, with gadzookas-more experience, than-me, will be willing to chime-in and correct my 'dribble', when the time-comes...

cheers...
j

[goninanbl00d]

Hey Sir A -



Might-be, in his-case, dunno but on the other-hand, the beam, at the HR is *tiny*...



yeah, it's just that whole 'tissue-response' thing, and since the things were spec'd for 3W for the 'standard' module, and 7W for the 'hi-power' (...heh, there's some 'marketing spin' for ya... they were spec'ing @ 630nm, so I think it was 'expected' to toss some power, and still be plenty-ok...



Indeed, yellow sine-waves and/or beam-cones are especially yummy...



I have seen them both ways... at-rest, they can have some 'air in the line' but that may-also be an indication of a 'vacuum leak' somewhere... others I have seen, have zero 'bubbles', at-rest... I think that would only cause 'troubles' if there were air-bubbles while running (would bunk-up the lasing-process...) and / or if it was actually leaking dye, somewhere...



Nice drawing...you're hired! And you're *very close* but the KTP-beam does pass-thru the dye-cell, and 'terminate' in a little 'pocket' in the BRF-mount....



Again, very nice.... Interesting concept....



Running 'on-deck' like this, (no loss thru fiber) and 'fresh' dye mix, you could probably expect closer to 40% or-better... I have it on 'good authority' that LS, when 'proving' these things, *consistently* achived average-powers of 17+ WATTS of Red (!!!) And our own Dear Doctor Photonbeam achieved 15+ with his-design...But, certainly, yes, 'erring on the side of conservativism' is a good-idea...

Still, if you used a 'hi-power' KTP sys, that was giving you 55+ W, (on a really good-day... you could - in-theory - pump with ~45W of 532 and get 15+ W of Red...and still have 10+ W of Green to stand on it's own... I'd, personally, go with as much Red and Blue (15+ W, also.. maybe even 20W of Blue...) as-possible, cause even 8-9W of 532 is gonna be visibly 'monster' vs the R/B %, here...



A "1/4-wave plate" is what is used to attenuate, and it works in a 'perpendicular' direction to the beam-path, so, it wouldn't really work, the way you are thinking.. (but 2 points for creativity... Even if you used a 'dichro' to 'blank' the way you are thinking, the 'range of travel' to blank-completely is very-large (...and thus, much slower) than 'retro-style' blanking...

If 'djCartBeforeHorse', there was not 'lurking' as a guest, as I'm sure he is, I'd gladly share a pic of this 'retro-style' blanking, specifically-designed for larger-beams, like this (hint: it's *not* the 'classic paddle-style'... ) Once I know he has his Variance-app FILED and an acc.#, maybe I'll post it.. PM's, only, till-then...

And, too, I think you'd end-up wanting to throw yourself off a bridge, trying to 'sync' 2x paddle-style blanking-setups + analog-direct w/ the blues... Best to 'mechanically' blank them all for intensity, and do 'color-mixing' via a (relatively) hi-speed dichro 'color-box'.. Again, since this would never really be 'intended' for graphics, I think even the 'sin' of this relatively 'crude-approach' would be forgiven in the face of some sort of result, like this: (pic not ours...don't even remember where I found it, otherwise, I'd post credit...)

(...don't even-know if this is *real*... but sure looks-good..

Anyhoo, this is all a bit of 'fantasy football', right now... But certainly, keep posting your ideas and thoughts and *never* be hesitant to ask... I can only hope that my 'Elders' like Pat and Sir Janders, there, with gadzookas-more experience, than-me, will be willing to chime-in and correct my 'dribble', when the time-comes...

cheers...
j

Well, half the details I don't know because I haven't seen one of these dye units in person (or a Laserscope, for that matter), and resources on these systems are few and far between.

But yeah, the values I used for calculations were very conservative, I'd heard that 40W is a good guesstimate for your 'average' Laserscope 800 series unit. Someone who has a properly tuned system, like yourself, would probably be able to get much more out of it.

The waveplate mount looked like it was rotational (with the stepper), and there was something about it being able to actuate quite fast (but it was Allen who said that, so I'm going to take that with a rather large grain of salt)

I guess there could be a way to make some form of electromagnetic actuator to rotate a waveplate fast enough, without using a mechanical, err, mechanism (which probably wouldn't be fast enough).

PM's, only, till-then...

I just love learning... Incommmiiiinngg!

I guess for beamshows, 7 colors would be enough. It'd certainly make for one helluva beamshow with 10+W of each color, though.

Worst comes to worst, the blue can also be galvo-blanked. Yeah, not ideal, but I guess 'lowering the bar' would cut it.

Either way, if this project does come together, 'absolutely awesome' would be an understatement- 40W may be bright, but nothing beats full color.

EDIT: Here's some math! Yay!

Assuming 55W of green power:

Keep 15W

Split 40W off for red conversion. Assuming 40% efficiency, that would mean 16W of red out- 1 more W than the green.

This would require a 27/73 beamsplitter, which doesn't exist. I guess a 25/75 would work, you'd get a hair more red out of it.

As we all know, blue is easily scalable. Just add more to taste

[dsli_jon]

The waveplate mount looked like it was rotational (with the stepper), and there was something about it being able to actuate quite fast (but it was Allen who said that, so I'm going to take that with a rather large grain of salt)

Uh, heh, yeah, more like a salt MINE...

Stay tuned... (...but don't hold yer breath....
j

[Laserman532]

assuming 55 watts of green?????

in a perfect world, with a perfect system, while standing on one foot, patting your head with one hand, rubbing your belly with the other hand while facing Mecca...

generally speaking...only the best of techs can get 40 watts with the gold cavity...lets say you are one of the best and you do get 55 watts...well, that is a very short list of individuals...now you can start on the red...40% conversion (assuming nothing gets damaged) should be a reasonable...target...

never mind.... goes back into hiding