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Thread: Laser warm-up question...

  1. #1
    Join Date
    Sep 2007
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    Near Portsmouth Hants
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    15

    Default Laser warm-up question...

    Hiya,

    I hope someone can help me out here because I'm not sure if what I'm seeing is normal or not.

    I recently bought a 2W CNI greenie and when it's first powered up there are two definite beams next to each other (I think it has something to do with the beam mode). It'll stay like this unless I run it at full power for 10 minutes and then the beams merge into one. If I turn it off (or down) for just a few minutes I have to run through the warmup again.

    Has anyone else seen this? - particularly any CNI owners out there.

    Thanks.

  2. #2
    Join Date
    May 2007
    Location
    Milwaukee WI
    Posts
    1,355

    Default

    Your laser is hopping modes during start up. One single beam is known as TEM00. Which is the beams transverse mode.

    While the crystals inside the laser are warming up you are seeing TEM01.

    Dont worry its completely normal.

    Read more about transverse modes here:
    http://en.wikipedia.org/wiki/Transve...de#Laser_modes

    -Max

  3. #3
    Join Date
    May 2007
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    Milwaukee WI
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    Default

    I must say 2 watts... WOW... POST SOME PICTURES!!!!

  4. #4
    Join Date
    Jan 2007
    Location
    Cupertino, California
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    2,130

    Default

    Yes, two watts is quite a laser! I want some pictures too!
    CLICKY!!!

    Admin: In the immortal words of Captain Planet: YOU HAVE THE POWER
    Admin: (To quit being a bitch)

  5. #5
    Join Date
    Oct 2006
    Location
    Cleveland, Ohio
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    2,332

    Default

    If this laser is meant to be a modulatable laser for shows, then this could be a problem, as it would go multimode if not used at 100% during a long stretch? The thermal regulator inside the unit should keep it from going TEM01 during lower power output after warmup, but he's saying it doesn't.

    That may not be normal.

  6. #6
    Join Date
    May 2007
    Location
    Milwaukee WI
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    Default

    Deleted... guess I cant read Thanks DrLava
    Last edited by mliptack; 12-21-2007 at 11:36. Reason: my own stupidity

  7. #7

    Default

    Quote Originally Posted by drlava View Post
    If this laser is meant to be a modulatable laser for shows, then this could be a problem, as it would go multimode if not used at 100% during a long stretch? The thermal regulator inside the unit should keep it from going TEM01 during lower power output after warmup, but he's saying it doesn't.

    That may not be normal.
    Only way to know is to try, eh? CNIs spec sheet lists a warm up time of <15 minutes. So turn it on, let it run for 15 minutes, then try hooking up your modulation and all. If its still outputting what looks like two noticeably separate beams, you'll want to contact CNI and get that fixed - TEM01 sucks and its not something you can readily fix on your own.

  8. #8
    Join Date
    Apr 2007
    Location
    Leicestershire, UK
    Posts
    137

    Default

    Sounds like a tec issue. I'd have thought that after the 15 mins warmup the laser should have stabilised even if you are modulating it. Definately would do as suggested and contact cni just to be sure.

    Sounds like you might have a nice setup there though chap.

  9. #9
    Join Date
    Sep 2007
    Location
    Near Portsmouth Hants
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    15

    Default Thanks for the input!

    Thankyou for all the helpful replies!

    From that Wikipedia link, It definately looks like rectangular transverse mode hopping between 00, 10 and now 20 - it seems to be getting worse.

    I'm going to get on the case to return it. Damn shame really as I've only just got it all built up and working, and I guess it'll have to be shipped from the UK to China via Texas - then back again!

    I've attached a few pics for those who said they wanted to see it but please excuse my messy wiring ! That said, it is still the most wonderful thing I've owned! I've discovered I really REALLY love lasers!!

    Thanks again for the advice and interest.
    Attached Thumbnails Attached Thumbnails Inside.JPG  

    Outside.JPG  


  10. #10
    Join Date
    May 2007
    Location
    Milwaukee WI
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    1,355

    Default

    Any pictures of it running?

    Or of just the greenie in operation?

    Otherwise it really looks nice! Great job!

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