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Thread: Lasing Medium??

  1. #1
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    Default Lasing Medium??

    ok, 532nm DPSS laser "lasing medium is- "Nd:Yag"

    what is the "lasing medium" for 635nm and 473??

    im filling out another variance and not too sure what to put here...

    -Marc

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    KNBO3 for 473nm
    on the red, its direct injection so you will need to find a technical term for the reds lens maybe. I could be way off here but this is what i am thinking.

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    DPSS lasers operate by frequency doubling infrared light which is created by the excitation of ND ions within a host material. The host can vary greatly but the most common ones are YAG (yttritium aluminium garnate) or for our 'little' greens & blues more traditionally Yv04 (aka vanadate - yttrium orthovanadate)
    Its the ND (Neodymium) that actually lases and like most materials has a number of laser transmission lines. The strongest is 1064 which doubles to 532 but lines at 914, 946, 1112, and 1342 are also used to create frequency doubled visible light at 457, 473, 556 and 671 respectively.
    They are all pumped using 808nm light - again in our case, and most commonly these days by the use of high powered laser diodes or arrays. To create different wavelenghths the Vanadate is coated to promote the line needed and surpress the other lines. So for a 473 nm blue laser you would coat the xtal so that it will not reflect the 808 pump light, and will reflect 946nm and 473nm so that an optical cavity can be formed. Also the coatings will need to transmit the other ir lines so that a cavity that amplifies these wavelengths cannot be created.

    The KNBO3 that DB refered to is actually the nonlinear freqency doubling crystal. there are a number of different materials used for this purpose and others include LBO and KTP (most common in green lasers). These are often chosen using their effeciency and tolerance to damage as well as cost in the selection process.

    As DB said 635 is direct injection - meaning there is a single semiconductor chip that forms a tiny optical cavity and path to generate red visible light.
    Bluray is also a direct injection device (and blue di diodes go up almost to 460nm) but as yet nobody had designed the technology to create wavelengths much in between using direct injection.
    Im sure it will happen in time. We just need the end use to be desired enough for the research to be funded - maybe this will come on the bcak of all this laser TV talk that seems so hot at the moment.

    Rob
    If you need to ask the question 'whats so good about a laser' - you won't understand the answer.
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    Quote Originally Posted by gottaluvlasers View Post
    ok, 532nm DPSS laser "lasing medium is- "Nd:Yag" what is the "lasing medium" for 635nm and 473??
    im filling out another variance and not too sure what to put here...
    Hey Marc -

    Umm, no disrespect, here, but I doubt your 532nm DPSS is using Nd:YAG for its' lasing medium - unless it is producing over 5 Watts of Green, like 7W - 60W, which I am guessing it's NOT, am I right?

    The label (if it is correct) on your green laser head should tell you the medium - if it says Nd:YAG, and is producing less than 5W of green, it is most likely actually using Neodymium-doped: 'Vanadate' (Nd:YVO4) and has the wrong sticker - here's a 'simple' article on why:

    http://en.wikipedia.org/wiki/Nd:YAG_laser

    http://en.wikipedia.org/wiki/Neodymi..._orthovanadate

    ...And as far as the 635, that should be a straight-up "semiconductor diode-laser" - yes, the 'lasing medium' is the semiconductor, but for purposes of your 'variance', you can just say "Diode Laser @ 635nm" - you don't need to get too technical with the CDRH - they'll 'get it' -

    In fact, it is better to BE a bit 'broader', rather than SO specific - I am not suggesting you OMIT, but rather INCLUDE - say, "DPSS Nd:YAG and/or Nd:YVO4Laser @ 532nm; from (lowest mW you will use, ie: 100mW) to 5 Watts, max; Diode Laser @ 635 - 670nm from XmW to XmW..." (this way, you're not LIMITING your approval to ONLY EXACTLY WHAT you listed, cause that's what you'll get approval for: nothing more, nothing less...) ya dig?

    You might also enjoy these articles:

    http://en.wikipedia.org/wiki/Diode-p...id-state_laser

    http://en.wikipedia.org/wiki/Laser_diode

    (helps clean up those 'dust bunnies' about the differences between diode lasers and DPSS lasers...)

    Anything else, you've got my number, dude...

    ciao
    - J
    Last edited by dsli_jon; 01-12-2008 at 02:19.
    ....and armed only with his trusty 21 Zorgawatt KTiOPO4...

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    Talking

    Quote Originally Posted by stanwax View Post
    DPSS lasers....
    *sigh* - Note to self: always remember to refresh BEFORE you post!!!!

    (good job Rob...) - hey, I'm a poet and didn't know it! (sorry..)

    peace...

    - J
    ....and armed only with his trusty 21 Zorgawatt KTiOPO4...

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    Quote Originally Posted by dsli_jon View Post

    (good job Rob...) (sorry..)
    Jon - at least you did answer his question - which im not sure all my babble achieved!

    Rob
    If you need to ask the question 'whats so good about a laser' - you won't understand the answer.
    -----------------------------------------------------------------------------------------------
    Laserists do it by the nanometre.

    Stanwax Laser is a Corporate Member of Ilda

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  7. #7
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    Cool

    Quote Originally Posted by stanwax View Post
    Jon - at least you did answer his question - which im not sure all my babble achieved!
    On the contrary Rob... I thought your reply was excellent. You covered the bases quite well.

    I do agree with Jon though; it would be better to be a little more broad in the definition to the CDRH, just so you aren't limited later on.

    Great info though.

    Adam

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    Well adam & jon CDRH variance is something that you know infinitely more about than I do

    Rob
    If you need to ask the question 'whats so good about a laser' - you won't understand the answer.
    -----------------------------------------------------------------------------------------------
    Laserists do it by the nanometre.

    Stanwax Laser is a Corporate Member of Ilda

    Stanwax Laser main distributor of First Contact in UK - like us on Facebook http://www.facebook.com/FirstContactPolymerCleaner
    www.photoniccleaning.co.uk

  9. #9
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    Quote Originally Posted by stanwax View Post
    Well adam & jon CDRH variance is something that you know infinitely more about than I do
    Hey Rob! -

    Yeah, Marc just needed a bit of 'tuning' from both sides - 'technical' (diffs between xtals and WHY and diodes vs DPSS, etc) and 'practical' (how not to 'pigeon-hole yourself with a regulatory agency, like CDRH...) - so, yeah, nice 'PL-teamwork' mate! ...we gave 'im some of the 'book' and some of the 'street' ...I expect we should see a nice big THANKS from Marc shortly...

    cheers...
    - J
    ....and armed only with his trusty 21 Zorgawatt KTiOPO4...

  10. #10
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    jon, buffo, stanwax, dreambeamz-

    thank you YET AGAIN!!! this forum is DEF turning into a savior. being one of the newer companies for laser shows, its great to know alot of you "old skoolers" like helpin a brotha out! (oh, by old skool i dont mean "OLD"...lol...) ahem...anyway-
    thanks for all the help you guys have been!!! hopefully one day i can return the favor.

    oh and for the variance i put solid state DPSS argon @1.21 jiggawatts. thats correct right?? lol....

    -Marc

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