Is it possible to bend a laser beam?

  • Thread starter Prabesh Pokharel
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  • #1
If so how can we do that?
 

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  • #2
jbriggs444
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It's just light. You can refract it with a lens or a prism. You can reflect it with a mirror. In fiber optic cables, internal reflection is the reason that the beam follows the fiber.
 
  • #3
DaveC426913
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You can refract it with a lens or a prism.
Or a star.

But for some smaller applications that might be impractical.
 
  • #4
boneh3ad
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Or a star.

But for some smaller applications that might be impractical.

I mean, isn't that technically still a (gravitational) lens, though?
 
  • #5
davenn
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I mean, isn't that technically still a (gravitational) lens, though?


yup, but a really awesome and cool scale :smile:
 
  • #6
jbriggs444
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I mean, isn't that technically still a (gravitational) lens, though?
Of course, in the case of a gravitational lens, the light is technically traveling in a straight line and we merely regard it as bent because of our prejudice toward the expected behavior of a space-time free from intrinsic curvature.
 
  • #7
phinds
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Of course, in the case of a gravitational lens, the light is technically traveling in a straight line and we merely regard it as bent because of our prejudice toward the expected behavior of a space-time free from intrinsic curvature.
I suspect that's a bit too advanced for this OP
 
  • #8
DaveC426913
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I mean, isn't that technically still a (gravitational) lens, though?
Yeah. The reason I mentioned it is that it is a lens that does not require the light to pass through - and be degraded by - a medium.
 
  • #9
DaveC426913
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I suspect that's a bit too advanced for this OP
Perhaps, but it might be unfair to second-guess the OP. They gave no clues about the intended application, or level of knowledge.
 
  • #10
phinds
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Perhaps, but it might be unfair to second-guess the OP. They gave no clues about the intended application, or level of knowledge.
Based on the original question, I stand by my statement.
 
  • #11
CWatters
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Material with graded refractive index. See also mirage.
 
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  • #12
CWatters gave what seems to me the closest answer to what the OP intended. When light goes from one medium to another and the two media have different refractive indices, the light beam will refract, or change direction sharply at the interface. One can fabricate materials that instead of having layers of discrete materials has a smooth gradient of refractive index, so that the light experiences a continuous change in refractive index and thus bends smoothly. Compare the pictures in these two wikipedia pages to give a visualization:

https://en.wikipedia.org/wiki/Gradient-index_optics
https://en.wikipedia.org/wiki/Snell's_law
 
  • #13
sophiecentaur
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Material with graded refractive index. See also mirage.
A gradual change between different refractive indices will make a laser beam follow a Curved Path, which could be a bit more striking than a sharp kink on the way through. For that to happen (visibly) in air, you would need a long path and some extreme differences in temperature for two layers. But a laser beam can carry a long way and be visible from the side (dust scattering etc) so it may be realisable. Perhaps a fuzzy boundary between two miscible liquids would work.
 
  • #14
Cthugha
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There are also solutions of Maxwell's equations that allow for shape-preserving self-bending beams without the need for further external manipulation once you managed to prepare the beam. See for example this viewpoint article from APS:
https://physics.aps.org/articles/v5/44

The research article is linked in the viewpoint article.
 
  • #15
phinds
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Anybody notice how we are just talking to ourselves here? The OP has not been back in the 8 days since he posted the question.
 
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  • #16
jbriggs444
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Anybody notice how we are just talking to ourselves here? The OP has not been back in the 8 days since he posted the question.
I am shocked, shocked to find that is going on in here.
 
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