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Questions about current limits of laser beam widths

  1. Jun 29, 2014 #1
    Hi there,

    I'm looking for some information on the current limits of the beam width of currently available lasers. I'm less interested in experimental setups that are not on the market yet, but I suppose if one of them is markedly different it would be interesting to know.

    Specifically, what is the smallest available beam width, what kinds of lasers can achieve it, and what are the specs for such a beam (i.e. power etc.)

    I've looked around a good deal so far and haven't found anything, so if you know or could just point me in the right direction I would be very thankful! This is a bit out of my field so any advice is appreciated.

  2. jcsd
  3. Jun 30, 2014 #2


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    For a Gaussian beam the usual limit is a few millimeters as it exits the laser system, and enters your free space optical setup.

    You can reduce this with a "beam reducer", which is simply a telescope, but the results are limited by the wavelength of the light. The theoretical limit would be the waist size for a Gaussian beam.

    With a bit of patience you can work your way through the Gaussian beam tutorial here:

    The technique I have used in the lab is to input the collimated laser beam into a very long focal length lens (e.g., 2 meter), and place my point of activity at the focal point. I've done this with 260 nm (deep UV) which had to be taken into a vacuum chamber. The focal spot was about 200 um, this is not the optical limit.

    Of course you can obtain smaller beams inside of fiber optics; 10 microns is easy enough, but you cannot maintain this once the beam is in free space.

    This may help: http://www.miyachiamerica.com/servl...tionalResources_Articles&file=01580000001ake3
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