Bend Light Around Coin - Arago Spot

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Lasers Arago Spot Science Experiments Bend Light Optics Photonics Poisson Fresnal Diffraction Celtic Mad Scientist
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  • Added: 23-Jun-08

Bend laser light around a suspended coin, into the center of its shadow. A cool display of the wave nature of light and an example of diffraction. A red laser or laser of any other color may be used.

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Bend Light Around Coin - Arago Spot

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  • Interesting

    lasers are always cool to experiment with. Ive stumbled across some neat effects.

    five stars for your video

    By LaserCo 1213733109 Reply Spam [+1] Moderate Up Moderate Down
  • CMON...

    THATS NOT BENDING LIGHT ITS JUST COVERING IT WITH A SMALLER OBJECT THAN THE LIGHT SIZE..

    By prccorp 1213673895 Reply Spam [-1] Moderate Up Moderate Down
    • Light bends (diffracts) into the shadow

      When we're talking about the Arago (Poisson/Fresnal) spot, we mean the bright spot in the center of the shadow, not the light around the shadow. The Huygens–Fresnel principle for light wave propagation says in this case that each point around the coin circumference will act like a point source, and in the center of the shadow they all constructively interfere, making the Arago spot.

      By CelticMadScientist 1213728624 Reply Spam Moderate Up Moderate Down
    • Reply part 2 of 2

      Another way to think of how cool this is: if you were to place you eye in the center of the shadow and look at the coin (don't do this though - it's not safe), then you wouldn't be able to see the laser because it's hidden on the other side of the coin. But you could see the faint light diffracting around the circular edge of the coin.

      By CelticMadScientist 1213728648 Reply Spam Moderate Up Moderate Down
4 Comments | Add Comment