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Thread: Frequency doubling into the yellow

  1. #71
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    Stopped because there is no market for yellow other then lab and a very small amount of medical. Lab folks are happy with 561, and medical buys OPSL right now because of the use of Dye for years means they only want 578, or they have to spend a decade doing a study to prove the new wavelength works on humans.

    Oxygen free crystal growth at 1500'C.. Ouch... Molten Fluoride salts is not a winner to work with outside of a lab.

    Sorry, but the economy is against us. Again, 30,000 to 100,000 USD to grow a useful Boule.

    There are two marketable wavelengths in the yellow and orange, and only two. 578 for medical, the small markets for Ophthalmic and Dermal. The second is 589 sodium line, but must be very precisely overlaying the atomic Sodium line. Even then the 589 market is lab chemistry /astronomy only, and that market right now is well covered by Toptica.


    To gain the medical market you need the beam quality of a good HENE and three to five watts of proven power that will work untouched/no adjustments for three to five years.

    A patent in the US is locking up OPSL for 578 Medical, and the skin doctors very much like disposable dye cartridges running off 20 Hz picosecond Green Yags. Those short pulse dyes use a solid polymer host, and they throw them away after 10K shots. The handpiece is a lump of very expensive dyed optical polymer with a transmit 532 reflect 578 mirror and a output coupler. It screws on to the green laser's delivery arm. Looks like a 14 cm length of 22 mm pipe. 1 Joule of fat beam yellow does a great job on just about any skin condition in a few shots.

    Right now there is no hesitation to pay 40-60K for an ophthalmic yellow, after all they had been paying twice that for decades for Argon pumped Liquid Dye.

    Yellow is easily obtained for video projectors from a blue pumped yellow phosphor, but no one wants to pay to develop laser to obtain 10-20 percent more color Gamut, unless its watts or tens of watts and off the shelf. How many of those Necsel Video yellows show up on Ebay? Answer, very few, too expensive and no demand in the initial market. "RGB" is good enough!.

    Find a massive industrial market that 578 does better then 532 and you'd have your laser off the shelf. Right now, no such major market exists. 5-10 mW of 561 or 578 is all the lab market needs, there is no scientific demand in cell sorting, optogenetics, or microscopy for more then 10-20 mW. We have 561 in a Confocal Microscope at work, and in the scheme of things, 10K for the Yellow Option in a 1.2 Million Dollar microscope is nothing.

    Steve
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    Last edited by mixedgas; 08-17-2020 at 03:31.
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  2. #72
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    Thanks for the information Steve.
    I did find some of these crystal sellers but none of them really respond.. either they have been spammed in the past by people wanting to buy single pieces and only want orders in the 1000's or they just have the listing but no stock.
    It's a shame boule growth processes are so crazy expensive for the ones we want other then ktp, yag, lbo .. assuming these found other uses within the market to keep up their demand to make it worthwhile for crystal growth installations.

    It's fascinating to realize there is this whole world/industry out there on crystal growth with amounts of money which is hard to even grasp.
    Unless there is a drastic revelation in crystal growth and the cost or time involved in growing these it's most certainly not going to happen.

    Kind of a shame nothing is creating the tension of demand to stimulate movement in this area of laser.

    One thing that always surprised me is the "OPSL is good enough" situation.. because opsl their life span goes down even when the unit isn't lasing and you'd reckon while a boule is expensive to grow: so is a single opsl unit. Once you've grown one you can make multiple units from that 30k boule and because of that come out much cheaper then an opsl even when such a unit is build to a high standard with proper tec control and maybe even an aom if modulation is desired.

  3. #73
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    About the only thing I can get off the shelf are frequency shifting crystals, that and the 400 Euro crystal for a few mW of 604 nm. Shift and mixing methods have to go intra-cavity on something far more complex then most of us would like to deal with.
    ~
    CNI was a good deal till the Chinese economy took off. They would sell you any wavelength you wanted, but not now.
    ~
    The parent line of 561, ie 1121 nm in Nd:hosts has 1/9h the gain of 1064. You'd think it would be all over the place in use, but no... Besides, most folks tell me 561 nm is too green to be a good yellow.

    ~
    Steve
    Last edited by mixedgas; 08-17-2020 at 09:11.
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  4. #74
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    yes I agree 561 is too green.. its a lemon green. I think most people want a contrasting color that sits far apart rather then a color that has a close resemblance to its counterparts (hence little projectors have the 2 shades of blue or violet lines other then a few users projectors out here. (although Im tempted to put violet (405nm) in some of my future builds.

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    The only true yellow is 575nm. Everything else looks green or or@nge to me. I tried growing crystals to raman shift but no luck. I can see a flicker here and there but nothing stable. CNI wanted 3k for 200 mw 575nm. You donít need much. 35mw is visible as a beam in air in direct sun.

  6. #76
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    Quote Originally Posted by kecked View Post
    CNI wanted 3k for 200 mw.
    Iíd be happy with 200mw of real yellow. The size of the unit and the price are the only downsides IMO. Iíd happily pay $1k for the units though. Maybe they will come down over time.

    David
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  7. #77
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    I don't think you can get into OPSL yellow for a grand. Although in fairness they probably don't make an OPSL yellow that only puts out 200 mw either, so...

    What about frequency-summation lasers? I've seen handhelds that make 10-20 mw of yellow (Makhov had one back in 2010 on the ILDA cruise) that were only $300 or so. Thinking that if you scaled that up a bit you could get an order of magnitude more power for somewhere close to a grand.?. Admittedly the modulation performance is likely to be awful, but at least it would give you some solid state yellow.

    Do any of the commercial manufacturers produce a frequency-summation lab module?

    Adam

  8. #78
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    Quote from Supplier as of this morning.. This is the laser crystal, doubling, high reflector, output coupler in a can.. No pump diode, no collimator, and no temperature control, ie heat sink/heater to 20'C above room temp, if needed, and I am thinking group buy or talking to DTR.

    Waiting to hear about power and beam specs, samples...


    561nm modules
    FOB unit price $558 at 10pcs
    FOB unit price $255 at 100pcs
    Delivery: 2 weeks

    Steve

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  9. #79
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    Ask for 575 and Iím all over it.

    one for projector and another for fun and a backup.

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    Shall I awake the dead? The thread isn't that old yet, but been quiet for awhile. I read each post with interest, yellow has been of interest to me for years, finally after 8 years as a laser hobbyist I have some decent power yellow from an ebay purchase, 2 watts of it, it cost me over two grand which I understand is cheap, even for surplus gear but it is turn key, the power supply and all in one unit. I put up info on it on another forum, the activity is quite slow over there, only three of us active but all friends: Coherent 577 nm 2 Watt Yellow Micro-X OPSL laser - Lasers - Laser Discourse

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    I shouldn't have spent the money due to other priorities, but these are so hard to find I jumped on it, will pay off that card later.
    Avatar is camera photo flash reflection. Doggy was found as a six week old puppy near dieing of thirst in the desert here in Qatar, she's a Saluki mix. I'm from Ohio, just working here.

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