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Thread: A small question!

  1. #1
    Join Date
    Oct 2007

    Default A small question!

    I have bought a laser module from China no-name at 100 euros. It's 532nm and 50mW. At the first start i put it on my house window when outside it were -4 -5 degrees Celsius. At the first 2-3 mins the laser point was a dot but after that it changed into 3 smaller dots in line. I swiched it off and put it in the house and turn it on again after a couple of minutes . After some time of working the 3 dots changed into a perfect dot and it stayed like that for and hour and passed. Afterall it was turned off a couple of times. Working the laser doesn't warm up at all. At a distance of 5m the diameter of the dot is 5mm.
    Can someone explain me this dot changing thing?
    Attached Thumbnails Attached Thumbnails DSCF4477.JPG  

  2. #2
    Join Date
    Jul 2005
    Lancashire UK


    Hi and welcome

    What happened to your laser is normal under the extreme outside temperture conditions

    what happened to your beam is called "mode hopping"
    inside the laser head is a TEC that stabalises the Crystal and pump diode by controling the temperature, this will only work correctly when the head is at ambiant temperature

    Hope this helps ..... Karl

    PS .... NICE CHOCOLATES by the way

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