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10082007, 10:42 PM  #1  
 
Class 1M Laser Join Date: Jul 2007
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Just curious, but what is the lowest possible divergence that can be archieved today (and in theory) I know perfect divergence (which is actually no divergence at all)isn't possible due to limitations by the laws of physics.  
10082007, 10:50 PM  #2  
 
Class 3R Laser Join Date: Oct 2006
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Its actually dependent on the beam diameter. Theoretically, with an infinitely large beam diameter you could have no divergence. The smaller you make the beam though, or the less coherent, or the longer wavelength, the more it diverges.
 
10092007, 01:00 AM  #3  
 
Class 3R Laser Join Date: Aug 2007
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well the pulsars divergance is in the negatives right? so negative infinity would be the lowest i think... which isnt really possible yet. negative divergance means it gets small first, then gets bigger. i think on the pulsar the focul point is like 18 feet or something.
 
10092007, 10:45 AM  #4  
 
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10092007, 03:13 PM  #5  
 
Class 1M Laser Join Date: Jul 2007
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Shouldn't it be possible to create a beam with.. say a diameter of 1mm with a divergence of 0,01mrad for example or even lower.(through air) Can something like this be done with a wavelength between 400 and 700nm. Or is there some (simplified) way to calculate this? I mean calculating the minimum divergence just by filling in a few variables (diameter, wavelength, density and refraction index of the medium the beam passes through)  
10092007, 03:22 PM  #6  
 
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Far field divergence has a simple form for a gaussian beam Divergence (defined as half angle) = wavelength/Pi/minimum spot size (e^2 radius)  
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