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Thread: Looking for an economical calibration light source at ~ 400nm

  1. #21
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    They make xenon lasers Steve? Wow. How fast can they pulse? How many lines and what wattage outputs?

  2. #22
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    not sure if this is an ar1 or 2 but you can have it if you want it.Click image for larger version. 

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  3. #23
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    mixedgas is offline Creaky Old Award Winning Bastard Technologist
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    Sodium does lase, in the IR, diode pumped, quite well. In fact its hush-hush these days.
    Diode pumped metal vapor lasers are making a comeback, just so far they are all IR.

    The the lower of the two sodium yellow "D" lines lases like crazy, however, you need a dye laser to "seed" it.

    Steve

  4. #24
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    IF RHD does not take that AR lamp, send me a PM.

    Steve

  5. #25
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    Quote Originally Posted by mixedgas View Post
    Not a mercury arc lamp, they have band spectra.
    High pressure lamps (like the amazon one listed) are still narrow enough, but they require expensive (>$50?) ballasts



    It's the ultra-high pressure ones (like in DLP projectors) where it gets too broad:



    I recommend any fluorescent lamp you already have in your house. It will have a mercury H-line at 404.7nm as well as a G-line at 435.8nm. They're easy enough to pick out especially if you were to zoom in on that area. Phosphor emission doesn't usually happen in this area because it wouldn't contribute much to the brightness of the lamp.



    I picked up one of the ebay argon lamps just now so I'll measure that when it gets here.

  6. #26
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    hecd will get you 325nm no?

  7. #27
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    ^I think you missed the economical part

    These spectrometers don't go that low anyway. 350 is pretty much the limit.

  8. #28
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    ive seen some go pretty cheap on ebay... but ya not cheaper than $20

  9. #29
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    Quote Originally Posted by mixedgas View Post
    IF not the AR1 lamp, why do I just not carefully pack up a penray and loan it to you.
    Steve
    Quote Originally Posted by logsquared View Post
    not sure if this is an ar1 or 2 but you can have it if you want it.Click image for larger version. 

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ID:	30093Click image for larger version. 

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ID:	30094
    Hey guys,

    For some reason the thread subscriptions stopped coming to me via email, and I assumed there had been no further activity on this thread.

    Thank you both for the very kind offers. In either case, I wouldn't feel right borrowing or accepting for free, something of this nature. Borrowing a bulb of any sort sounds like a recipe for disaster with two-way shipping involved (and I'm in Canada). Similarly, I'd want to pay you for that AR bulb.

    So if one or either of these offers is still on the table, I would love to purchase either item. When I initially said that I was looking for an "economical" source, I didn't mean to imply that I needed something for free I was really just thinking that I needed to avoid a really expensive "lab grade" calibration source. But I'm quite happy to spend some money to get something accurate and useful.

    That said, I'm going to go try a few fluorescent bulbs and see what I can identify. If that ends up being sufficient, I'll update the thread.

    EDIT: That was a great suggestion. The G-Line was weak, but it was exactly what I needed. I re-calibrated my meter using the G-Line, plus 473, 532 and 589nm DPSS. It might make sense for me to do something similar with a mid 600s range known wavelength also. Do you think something as simple as this:
    http://www.ebay.com/itm/B7A-Miniatur...ht_1904wt_1139
    Would allow me to calibrate using the (relatively lower powered) lines at 627 and 630 ?
    http://physics.nist.gov/PhysRefData/...neontable2.htm

    It might be challenging in that some of Neon's other lines would be fairly powerful. In the end, I'd be calibrating with:
    - CFL G-Line at: 435.8
    - Neon at: 461
    - DPSS at: 473
    - DPSS at: 532
    - DPSS at: 589
    - Neon at: 627 or 630

    Even though that the calibration requires a 3rd order polynomial, I think I can use as many calibration points as I want in computing it.
    Last edited by rhd; 02-05-2012 at 12:03.

  10. #30
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    This is what shows up for me in neon's red spectrum (glow-lamp indicator):


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