(University of Michigan: Ann Arbor, MI) -- A dramatic and surprising magnetic effect of light discovered by University of Michigan researchers could lead to solar power without traditional semiconductor-based solar cells.

The researchers found a way to make an “optical battery,” says Stephen Rand, a professor in the departments of electrical engineering and computer science, physics, and applied physics. In the process, they overturned a century-old tenet of physics.

“You could stare at the equations of motion all day, and you will not see this possibility,” says Rand, one of the authors of a paper about the work published in the Journal of Applied Physics. “We’ve all been taught that this doesn’t happen. It’s a very odd interaction. That’s why it’s been overlooked for more than 100 years.”

Light has electric and magnetic components. Until now, scientists thought the effects of the magnetic field were so weak that they could be ignored. What Rand and his colleagues found is that at the right intensity, when light is traveling through a material that does not conduct electricity, the light field can generate magnetic effects that are 100 million times stronger than previously expected. Under these circumstances, the magnetic effects develop strength equivalent to a strong electric effect.

“This could lead to a new kind of solar cell without semiconductors and without absorption to produce charge separation,” says Rand.

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