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Thread: Blue laser 445nm

  1. #21
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    Tocket,

    I would like to get your thoughts on this:
    The little graph I posted in this thread shows that 445nm stimulates the 'blue cones' twice as much as 473 does. 473 appears brighter alone than 445 alone because 473 nm significantly stimulates the 'green' cones as well, while 445nm doesn't.
    So using 100 mW of 445 with the proper amount of green to get a 473-like blue (impossible to get the exact same, I know, but will be close enough) would need approx 200 mW of 473nm alone for the same brightness.

    I agree that brightness isn't perceived linearly by the eye but in our application you don't want a laser to be exactly twice as bright as ...., we just want big powerful, bright laser for the money we can spend. The mW scale simply allows us to estimate what a laser can do (how much smoke, how big a venue etc.)

    Unfortunately 445nm lasers come in 500mW increments but maybe that will change, or the price will drop. The point is that with 500mW 445nm (with green mix) you will have the equivalent of 1W 473nm and with the option to have a deeper albeit weaker blue line. - that is my assessment, can Arctos confirm this?

  2. #22
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    Default 50mW

    There are also 50mW single mode diodes available. so you will even get nice beam specs. This would be a nice addition to our 100mw 473nm I think, and probably they will not cost you a fortune....
    I want one.....

  3. #23
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    I knew I forgot something, the book doesn't have a good cone response diagram. However, I think you're much better off using the color matching functions.

    I've crunched some more numbers on 473nm simulants. Yes, it appears that the 445+532 mix can be very effective. You can get the hue of 473nm by mixing 5 parts of 445nm with 1 part of 532nm. The luminous efficacy of this mixture is 1.8 times higher than that of monochromatic 473nm light. The brightness efficacy ratio should be even higher because of the brightness enhancement in this region.

    Now, 405+532 isn't so bad either. The ratio here is 19:1 to achieve the 473nm hue. The saturation is a bit worse than 445+532 and the luminous efficacy is roughly half that of 473nm.

    I would love to have the lasers to test this. Unfortunately I don't have any 445, 457 or 473nm lasers.

  4. #24
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    @ tocket,
    thanks for the number crunching. Its interesting to see we came to the same conclusion within 10% !

    It appears that the 405nm is too low on the blue cone response curve to give any leverage to getting blue with a green mix.


    @mccarrot

    those 50mW diodes sound interesting, do you by any chance have a link to them?
    If they come out in a 100mW version I'm sure to give it a try...

  5. #25
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    Hmmm, I just checked the price,

    a 500mW multimode cost about the same as a 50mW single mode...

    Both arround the 2600 euro, so I think i will be playing with 405nm only...

    But how to add 405nm with 473nm without too much losses? PCB Cube?

  6. #26
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    Oh well, just wait a year or two

    I had to dig up this old thread:
    http://www.photonlexicon.com/forums/...?t=2481&page=2

    Touches upon the same topic on both sides of the spectrum (literally).
    Post #26 says:
    Quote Originally Posted by Zoof View Post
    OK, here is a though:

    Take 650nm and a 635nm diode of the same power. Mix green with the 650nm beam so the final color matches the 635nm color.

    Which beam will be brighter, the 650+green or the 635 only beam?
    Its probably more sensible to take 658nm though.

    Tocket, would you crunch the numbers again but for red this time? -just to see how it works out on the red side......

    (although I expect the gain only to be marginal, not as large as on the blue side)
    Last edited by Zoof; 10-08-2008 at 07:01.

  7. #27
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    Quote Originally Posted by Zoof View Post
    Hey Mccarrot,

    good to see our small country below the waterline being represented more and more, here on PL !

    I have no experience with 405 (or 445) so this is all prediction based on those charts. But yes it should work. Look here for actual results: http://www.photonlexicon.com/forums/...ead.php?t=5460
    I'm not sure about the tones of blue achievable, there might be a `spectral gap' there but we should ask thesk8nmidget.

    445 seems nice because it is close to the peak of blue cone response.

    Do you have those movies online somewhere?

    cheers!
    The Dutch are taking over :-)

    We need JeroenVDV and we are complete :-)

  8. #28
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    [quote=Anthony;63410]The Dutch are taking over :-)
    [quote]

    Well then why not post a movie of lasershow made by a Dutchman this weekend

    Einstein @ work:

    http://video.google.nl/videoplay?doc...ugo+awakenings

    Too bad google video fucks up the quality, but I can tell you in real live it looked 100000x stunning...
    Last edited by mccarrot; 10-08-2008 at 09:22. Reason: typo

  9. #29
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    Quote Originally Posted by Zoof View Post
    Oh well, just wait a year or two

    I had to dig up this old thread:
    http://www.photonlexicon.com/forums/...?t=2481&page=2

    Touches upon the same topic on both sides of the spectrum (literally).
    Post #26 says:

    Its probably more sensible to take 658nm though.

    Tocket, would you crunch the numbers again but for red this time? -just to see how it works out on the red side......

    (although I expect the gain only to be marginal, not as large as on the blue side)
    By power you mean radiant power, right?

    Well, it only takes 8mW of 532 to make 1W of 650 look like 635 (6mW for 658). Adding that little green isn't going to make a big difference to the luminance or brightness. For 650 you gain 7% in luminance and for 658 8%. Considering the 635 has 3 times the luminance compared to 1006 mW of 658+532 it really does seem like 635 is the better choice.

  10. #30
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    [quote=mccarrot;63419][quote=Anthony;63410]The Dutch are taking over :-)

    Well then why not post a movie of lasershow made by a Dutchman this weekend

    Einstein @ work:

    http://video.google.nl/videoplay?doc...ugo+awakenings

    Too bad google video fucks up the quality, but I can tell you in real live it looked 100000x stunning...
    Thats a hugo show right?

    I can see the CRAZY crowdscanning flame post comming
    Thats some sick laser"show"!!!

    Sorry for the OFFTOPIC guys.

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