In Einstein’s theory of general relativity, black holes are known for their ability to trap both light and matter by warping spacetime – creating a boundary known as the point of no return. While black holes have long captured the imagination of scientists and the public, their hypothetical opposites, called white holes, remain mostly theoretical. A white hole is thought to do the reverse: instead of pulling matter in, it would push light and matter out.
Now, researchers have developed a novel optical device that behaves in a surprisingly similar way to these cosmic phenomena.
Described in Advanced Photonics, the device can act like an optical black hole or white hole depending on the polarization of incoming light. It’s based on a principle called “coherent perfect absorption,” where light waves interact in just the right way to either be completely absorbed or entirely reflected.
By forming a standing wave and directing it toward an ultrathin absorbing material, the device can absorb nearly all the light or let it pass through – mimicking the way black holes absorb light or how white holes would theoretically emit it. In essence, it’s a lab-made system that can either trap light or push it away, depending on how that light is polarized.
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