If you think you know what a shadow is, think again.
More simply, it challenges our understanding of what a shadow is.
Our demonstration of a very counter-intuitive optical effect invites us to reconsider our notion of shadow.
In the experiment, a high-power green laser passed through a ruby cube, illuminated from the side by a blue laser. The green laser increased the ruby’s absorption of the blue light, creating a darker area that appeared as the green laser’s shadow.Image: Abrahao et al.
They consequently wondered if this could be replicated in a lab.
How did they know it was a shadow?
Regardless, the demonstration expands the possibilities of controlling one laser via another.
Researchers showed that a laser beam can sometimes act like a solid object and cast a shadow that is visible to the naked eye. In the above image, the shadow appears as the horizontal line traversing the blue background. Credit: Abrahao et al.
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