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

[dsli_jon]

hey Gon..

Thanks for posting that curve... Interesting, that, in-fact, 532 appears to have better absorption vs 476 - 488... Guess I'm not sure, then, what 'mix'-exactly, is used in the CW Argon / Dye sys'... Nonetheless, that underscores the truth of:

...From what I've read it's near-impossible to get a CW dye laser using a cell/cuvette- a dye jet is needed.

...which (besides, clearly, the particular 'mix' being 'optimized' for the Argon-lines, in such-sys'...) is why those can, indeed, get the dye going, with only 8-9W of CW-pump... cause 'doz be jets vs cells...

Thanks for the add...
j

[goninanbl00d]

hey Gon..

Thanks for posting that curve... Interesting, that, in-fact, 532 appears to have better absorption vs 476 - 488... Guess I'm not sure, then, what 'mix'-exactly, is used in the CW Argon / Dye sys'... Nonetheless, that underscores the truth of:



...which (besides, clearly, the particular 'mix' being 'optimized' for the Argon-lines, in such-sys'...) is why those can, indeed, get the dye going, with only 8-9W of CW-pump... cause 'doz be jets vs cells...

Thanks for the add...
j

I believe that the 514nm line is used to pump the dye, and the 488nm has little effect.

If 532nm is used, it may be possible to get the dye cell lasing at lower powers.

[dsli_jon]

Hey G -

I believe that the 514nm line is used to pump the dye, and the 488nm has little effect.

Point, well-taken....



...however, though the 'absorption-efficiency curve' clearly shows the peak between 500 and 560-ish nm, I still-submit 'efficiency' can also be a matter of what-optics / particular tuning gets-used in a given Argon-head, and the dye-mix - ie: check the 'fluorescence' curve of R6G from that same site (...note the 'excitation-line' used) :



...and this makes-sense, since you typically find 'multiline' optics in ie: the Coherent-med sleds, w/ Ar / Dye-combos... if 488 were 'hindering' and/or totally useless, you'd expect to find single-line / mode optics, perhaps even prism / etalon combos in those sleds...

I really think, too, dye-mix has got a lot to do with it, ie: Coumarin shows highest response-peaks at 480 and 515 - *perfect* for pumping w/ an Argon, so, who-knows what exact 'cocktail' LS and/or Cohr / SP use... additives, etc, etc...

If 532nm is used, it may be possible to get the dye cell lasing at lower powers.

did you mean 'dye jet'?

peace...
j

[goninanbl00d]

I'm not perfect, I may or may not be wrong.

However, the graph suggests that Rhodamine shows some absorbancy at 480-490nm. It's not much, but the absorbancy's certainly there.

Rhodamine is one of those dyes which can lase extremely close to the excitation wavelength. Most times it comes out as what can be aptly described as a piss-yellow (around 560nm), and can be up-tuned from there.

Judging by the color of the dye from the only photo I've seen of a 600 series dye module (from 'prodjallen', surprisingly, who's lucky enough to have been able to get his hands on a dye cell), it looks like Rhodamine B, not 6G. Rhodamine B has higher efficiency in the red spectrum, if the graphs do not lie.

And yes, I did mean dye jet. I keep getting the two mixed up.

[dsli_jon]

Hey G -

Up late, too, huh? I'm backing up our work-server and it's taking f o r e v e r...

I'm not perfect, I may or may not be wrong.

Lol, no worries, man, we're just chattin, here... But, you actually make a great point:

Most times it comes out as what can be aptly described as a piss-yellow (around 560nm), and can be up-tuned from there.

..you're right - actually, Exciton's data-sheets seem to indicate that (at least their mix of it...) 'Rhody' puts-out more at (like you said) 560, and again at 590 (R-B?), though it does-extend into the 600s...

...So-then, I wonder if, indeed, LS's mix might-not be a 'blend' of R-B, and perhaps, either DCM or Kiton Red, both of which extend-further into the 600s, especially Kiton, since it shows a fair-bit of 'gain' in the 'advertised output-range' (630nm) of the LS-600s... If it were only 'pure' Rhody (either 6G or B) you'd expect much-more 'hype' from LS about 'yellows', vs the 630 (and beyond, especially when you take-out the birefringent-filter - once you do that, it puts out a much 'deeper' Red, which, judging-just 'visually', looks a lot closer to 640-650...)...

...Cool stuff...

And yes, I did mean dye jet. I keep getting the two mixed up.

No worries, I got ya...

Oh, ps - here's some old-shots that might be of interest to ya:
...I'll have to see if I have any other shots, just of the dye-cartridge...

peace...
j

[goninanbl00d]

Hey G -

Up late, too, huh? I'm backing up our work-server and it's taking f o r e v e r...



Lol, no worries, man, we're just chattin, here... But, you actually make a great point:



..you're right - actually, Exciton's data-sheets seem to indicate that (at least their mix of it...) 'Rhody' puts-out more at (like you said) 560, and again at 590 (R-B?), though it does-extend into the 600s...

...So-then, I wonder if, indeed, LS's mix might-not be a 'blend' of R-B, and perhaps, either DCM or Kiton Red, both of which extend-further into the 600s, especially Kiton, since it shows a fair-bit of 'gain' in the 'advertised output-range' (630nm) of the LS-600s... If it were only 'pure' Rhody (either 6G or B) you'd expect much-more 'hype' from LS about 'yellows', vs the 630 (and beyond, especially when you take-out the birefringent-filter - once you do that, it puts out a much 'deeper' Red, which, judging-just 'visually', looks a lot closer to 640-650...)...

...Cool stuff...



No worries, I got ya...

Oh, ps - here's some old-shots that might be of interest to ya:
...I'll have to see if I have any other shots, just of the dye-cartridge...

peace...
j

Nah, not up late. I'm in Australia.

By the time you do get Rhodamine up into 600nm or thereabouts, the efficiency's pretty much dropped out the bottom of it.

The dye used in the Laserscope 600s is a Barbie-pink (for want of a better description) color- looks nothing like Rhodamine, come think of it. Even though Rhodamine B is supposedly optimized for red, it doesn't look any better once you start hitting the higher red range (around 630nm).

If they did use Rhodamine it'd be useless for their purposes. The dye used in photo-dynamic therapy is absorbant at 630nm, and that's what activates it and makes it work its magic in the tumour.

As for the shots, I've seen them before, but thanks for the heads-up. prodjallen seems to be the only person on the internet who has the documentation and a working dye cell.

It's an interesting cavity design, how the pump beam is introduced through the HR, forming a very nice yellow with the red inside the cavity. The Coherent x99 series simply focus the beam through the dye jet- at no point is the beam inside the resonant cavity.

Dye lasers have always had my interest for a while now. There's that something special about them that you don't get with most other lasers available to hobbyists. (maybe it's the tunability? ) I'd start playing around with them, if they weren't so damn expensive.

[tocket]

One thing I have yet to understand about dye lasers is why triplets are always thought of as something bad. As the triplet state is much more long-lived it should be quite useful for achieving population inversion at lower pump power densities.

For example Ru(bpy)3 has an absorption maximum at 450 nm in water and emits at 625 nm and the triplet state has a lifetime of 600 ns at room temperature.

[goninanbl00d]

One thing I have yet to understand about dye lasers is why triplets are always thought of as something bad. As the triplet state is much more long-lived it should be quite useful for achieving population inversion at lower pump power densities.

For example Ru(bpy)3 has an absorption maximum at 450 nm in water and emits at 625 nm and the triplet state has a lifetime of 600 ns at room temperature.

Only problem here is, once they get pumped up into said triplet state, they are no longer capable of lasing, and instead begin absorbing the lasing wavelength.

Hence the need to get them out of the beam path as fast as possible.

[dsli_jon]

Nah, not up late. I'm in Australia.

Ah, then you're up early... Jus kiddin...

By the time you do get Rhodamine up into 600nm or thereabouts, the efficiency's pretty much dropped out the bottom of it.

Yeah, I do-think there must-be more to both the Cohr / SP Argon-pumped med-sleds- mixes and the LS-mix, than 'meets the eye'...

...Sir Mixedgas, what sayeth you? LS-mix: DCM? Kiton? Blend? Strawberry shampoo?

prodjallen seems to be the only person on the internet who has the documentation and a working dye cell.

Oooh, I dunno about that... ...we've got two... ...plus, I wouldn't really put too-much stock in what 'DJ-doublespeak', there, has to tell you about his 'arsenal'...

It's an interesting cavity design,...

Indeed... truly intriguing, especially, as you say, 'tuning' the 'BRF' thru the yellows / oranges, then into the blood-red... very, very cool...

Dye lasers have always had my interest for a while now...I'd start playing around with them, if they weren't so damn expensive.

Expensive? m8, when was the last time you checked the prices on these things? They're cheap as-dirt, now! Of course, you'll rack-up a few $K with a proper-KTP, and mods, and optics, etc, etc, but first-time I bought a 600, it was like $2500. - now, you can snag them for far-less than a $G! (granted, that's off of 'e-who-really-knows-what-condition-it's-in-Bay'... ) But even-so, you should be able to find one, tested, etc, from a 'reputable-reseller', for as low as ~$1500. tops...

Oh...yes, well, I guess I'm making some 'assumptions' about your-particular 'definition of expensive', too, Sorry... I need to remember, not everybody does this for a 'living', and, thus, may-not expect to have-to bleed-money at every turn...

cheers...
j

[goninanbl00d]

So you have your hands on one of these? Awesome

Problem is, so far, Allen's the only one who's got photos of one of these beasts running. Even though there's sure to be more out there, he's the only one who has one working, and has photos of it. That's assuming the photos are his, and not stolen.

And yeah, I'm still at school. Although $1500 isn't much (considering a new Coherent 899 system costs upwards of 100G), it's not money that I can dig up at a moment's notice, unfortunately.

Heck- you can get a Coherent 599-05 system for under $1500 (with controls and dye circulator).

EDIT: Allen's pics of the dye unit: http://www.flickr.com/photos/prodjal...th/4686606969/