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Optical problem that eludes me

  1. Jun 4, 2008 #1
    At my location, the Sun's gross energy is .6kW/M2 with roughly 40% of that energy being IR.

    Now on to my question..

    Why can't we collect, filter and collimate that IR to be used in laser cutting applications?
    I understand divergence will be an issue but if the divergence is filtered out to say .5ยบ, there should still be adequate energy for the application. This energy could be piped through fiber optics and multiplied by the number of collecters and mirrors.
    If filtering out divergence causes too much of a loss, why couldn't it just not be filtered and accept the small amount of undercutting in the application? 99.9% of all laser cutting applications involve materials that are less than 1mm in thickness and/or etching of material surfaces which divergence wouldn't be an issue at all. I'm kind of at a loss since the Sun's rays are free, yet laser energy is at a 90% loss.

    If I could only harness say 10% of the available IR, it would still be feasible to manufacture a machine whose collecting surface is 100M2 and produce better than 2kW of output.

    Am I missing something??
  2. jcsd
  3. Jun 5, 2008 #2


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    Staff: Mentor

    100 m^2 is a big lens! And it has to track the sun. It just isn't very practical.
  4. Jun 5, 2008 #3


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    Science Advisor
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    Gold Member

    Hi texnoz, welcome to PF.

    Yes, and if you

    1. Look at the specs of an existing IR laser;
    2. Design your sun-routing system to match these specs; and
    3. Compare the costs

    you will see what it is.

    I work with an IR laser. Among other things, I need constant power, I want to modulate it on a millisecond time scale, I want to run the equipment at night and on rainy days, and I don't want to install a giant mirror on the roof of my research building. When you're adding up the costs, make sure to include workarounds to these issues.
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