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Thread: cylindrical lens positioning

  1. #1
    Join Date
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    Default cylindrical lens positioning

    Where to position the cylindricals, both the recommended distance relative to the diodes, as well as scanners?

  2. #2
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    What are the cylindrical lenses being used for?

    Typically, they are used to change the aspect ratio of the asymmetric laser stripe out of a diode and make it more of a square. This will also reduce the divergence of the beam along the axis that it has been expanded while leaving the other axis unaffected. If the available room is unlimited, then using longer FL lenses with the same relative FL compared to each other will make alignment much easier and reduce the aberrations that these lenses can introduce.

  3. #3
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    Default

    Quote Originally Posted by planters View Post
    What are the cylindrical lenses being used for?
    Multimode diode beam shaping

    If the available room is unlimited, then using longer FL lenses with the same relative FL compared to each other will make alignment much easier and reduce the aberrations that these lenses can introduce.
    Thank you. I had the idea that there were more strict rules that needed to be followed such as specific distance between the collimator and the cylindricals as well as the cylindrical lens pair and the scanner mirrors.

  4. #4
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    Thank you. I had the idea that there were more strict rules that needed to be followed
    There are none. This is easy and there are no subtle, rules governing this spacing.

    You will find that the inherently large divergence from the diode itself, even after the beam has passed the initial collimator lens, will add to the defocusing power of the first cylinder lens, which of course is a negative cylinder. Therefore, the relative spacing between this lens and the positive cylinder that re-collimates the beam after it has been expanded, will chance slightly as the pair is placed further from the diode.

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