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Thread: Frequency doubling into the yellow

  1. #1
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    Smile Frequency doubling into the yellow

    Hey, Iím a chemist and have a question which might be straightforward for many of you!


    Iím made compounds having an extraordinary high second harmonic response at 400/800 nm. I want to now try to make a yellow laser, at 570-590 nm by their irradiation at 1140-1180 nm. There is a market for yellow lasers having watt-level output power level. But first, you need a higher power laser which operates at 1140-1180 nm.


    Thereís reason to believe that if it were possible to find a relatively high power laser at 1140-1180 nm, these or similar materials would become a reliable yellow laser source. The 1140-1180 nm range is relatively low energy, so it would hopefully not damage the materials.


    So far, it hasnít been possible to locate such a laser There are lasers sources - in the 100 - 200 mW range- but this is too low (He-Ne, Ba(II) and Pb(II)).

    Any ideas?

    Thanks!

    Fenton

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    I probably can help with that...
    I need to check a book in the office in the morning.

    Steve
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  3. #3
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    I think that you have hit the nail in the head-- the reason why yellow lasers are expensive is not the lack of doubling crystals (generally, any crystal that works for 532nm would work fine in the yellow with a slight temperature/angle/polling etc change) but there are few efficient laser mediums lasing at ~1150nm.

    The current state of the art for commercial work is optically pumped semiconductor (OPS) materials, such as is used in the coherent taipan https://www.coherent.com/lasers/lase...0-nm-to-577-nm (6W in the yellow, ~10% electrical-optical conversion efficiency).

    There is also work being done with Yb:Fiber lasers; by playing some tricks with nonlinear optics in the fiber the laser guide star community has been able to achieve tens of watts in the yellow with quite good conversion efficiency, although this is still a topic of active research so few if any commercial systems are available yet.
    ex http://onlinelibrary.wiley.com/doi/1...201400055/full
    Here they achieved 50W output power at 589nm (selected to match the sodium D2 absorption) with 82% conversion from 1178nm in the doubler. Took almost 500w from their 976nm pump diodes and ~$50k worth of fiber and related optics to generate the 1178nm beam to double though... Most of that work was to push all of the way to 1178nm.

    If you are willing to work at 560nm you can cut out the first nonlinear conversion stage which should push the efficiency ~5 times higher, pushing the electrical->optical efficiency up to ~25% with room to achieve >30% with careful optimization. As far as I know, no one has tried this, probably because there is not research funding available for the goal of 'really pretty yellow laser for laser show applications'.

    Best of luck with your endeavour! If your goal is to develop nonlinear materials your best bet is probably to just buy a raman fiber laser, ex http://www.ipgphotonics.com/en/produ...rlm-lp-50-70-w but they won't be cheap. I would expect a solid 5 figures depending on power wavelength etc. If your goal is to sell a yellow laser, your are probably better off learning how to grow OPS materials or combining red and green diodes

  4. #4
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    Hi krazer and mixedgas,
    Thanks for your advice and time!
    On the same page where IPG mentions 1178 nm lasers, they also state ďCustom wavelengths are available, including visible frequency doubled modelsĒ.
    You mentioned the Genesis Taipan ď460 nm to 577 nmĒ model from Coherent. I defer to your experience, but speaking as an organic chemist, its blow-up schematic looked like spaghetti. If my assessment were to be true, then there might be implications for the market.
    Actually, when I lived in the CA Bay area, I called Coherent to see what sorts of materials they would foresee being useful over the next five to ten years. Eventually, it was possible to speak with someone. He patiently explained that they werenít going to talk with anyone who they didnít already know (fair enough).
    The review article, ďVersatile Raman fiber laser for sodium laser guide starĒ will be very helpful (thanks again!).

    Today I (also) want to look into frequency tripling, My assumption is that this mode would lower the incident power levels.

    It would be great to continue this conversation. My goal is to assess the logic of grounding a start-up.
    Fenton

  5. #5
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    I was suddenly invited to a St. Patrick's day party after judging the regional science fair today. Since the party was down the road from campus I forgot to check my favorite reference in the library. There are some common solid state lasing materials that have lines where you want to go, I just need to pull the book.
    They are hard to get lines in that you need to suppress a main lasing line that shares the same upper state, however dielectric coated optics today are a few orders of magnitude better then when the original research was done on these materials in the 1970s.. I do already have optics sets for lasing 1121...
    I will get back to you.

    Steve
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    Hey, in southern Texas they likely don't even celebrate St. Patty's day. If there are a lot of green-colored items, then let's hope that they don't lase.

    Grounding a start-up always has a challenge. In this case, it's the economic advantage of a new portable yellow light source. The gamble is that the efficiency of the compounds in question will allow power levels on the order of 1-10 W. For example, Dragon Lasers offers one up to 50 mW, at 589 nm, beam diameter 2 mm, device dimensions 26 x 200 mm for $469 (http://www.dragonlasers.com/Yellow-Laser-Pointers.html).

    Thanks again, I don't want to be chasing ghosts or whatever.

    Fenton

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    You get me a good watt 589nm under 1k and Iíll buy. One 100mw under 200.00 Iíll buy.

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    Quote Originally Posted by kecked View Post
    You get me a good watt 589nm under 1k and Iíll buy. One 100mw under 200.00 Iíll buy.
    I couldn't agree more with this statement. I would be in for this too!

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    Oh I should add that modulates well and has decent divergence though for lumia Iíll take anything

  10. #10
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    Well, I found a ND +3 host that that lases close enough for doubling to yellow in the book. Now I just need to see if anyone manufactures the crystal.

    Steve
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