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研究人员发现光也能产生磁效应 可开发出光电池 这种制造“光电池”的方法可能推翻物理学的百年教条。光具有电性和磁性，但一直以来，科学家认为光的磁场效应非常弱，可以被忽略。 密歇根大学电工程与计算机科学、物理与应用物理系教授斯蒂芬·兰德和同事发现，当光以适当的强度通过一种绝缘材料时，光场所产生的磁效应比以前预期的要强一亿倍，在这种情况下，磁感应强度相当于很强的电效应。该方法的原理是此前未曾研究过的“光整流”，研究人员威廉姆·菲舍说，传统光整流中，光只能通过其电场效应将一些特殊的对称晶体材料中正负电荷分开形成电压，而新研究发现，在适当的条件下，光在其他材料中能通过磁场效应产生“光整流”。 兰德解释说：“在传统太阳能电池中，光进入材料被吸收，产生热量分离电荷。在我们的方法中，光不是被吸收，而是将能量存储在磁矩中，这将带来一种不需要半导体的新型太阳能电池，热负荷很低。强光也能产生很高的磁感应强度，最终提供一种类似电容供电器的光容式电源。” 新技术将使太阳能发电更廉价。研究人员预计，使用改良材料可使太阳能转换效率达到10%，这相当于目前商业级的太阳能电池。今年夏天他们将在实验室里利用激光研究，然后拓展到太阳光。 “目前制造太阳能电池需要大量的半导体加工工序。而我们只需一些镜片来集聚阳光，一些纤维来传导。玻璃就是很好的材料，透明陶瓷可能会更好。不需要复杂的工序。”菲舍说。 分享到：
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最新评论
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huxingong 2011-04-18 17:02强悍！！ 期待啊
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心语 2011-04-18 20:57厉害！期待中！可能又是一次能源变革！
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cloudfd 2011-04-19 08:57先看看实验效果
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tassy 2011-04-19 11:29强烈期待啊 ！！
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tangshuming 2011-04-19 13:41等待实验结果
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doucan 2011-04-19 19:36希望能早日应用这一技术。
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殇辉痕 2011-04-20 08:39感觉与之前某隐身衣研究有类似之处，通过材料和结构实现谐振
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09njtpw 2011-04-20 09:37任重而道远呀
不过还是很期待
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eicp 2011-04-20 11:33没错。我们老师说过，如果早先对光子的研究像电子一样重视，一定会有一个光的应用世界。
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eicp 2011-04-20 16:39Solar power without solar cells: A hidden magnetic effect of light could make it possible
ANN ARBOR, Mich.—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,” said 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. We’ve all been taught that this doesn’t happen,” said Rand, an author of a paper on the work published in the Journal of Applied Physics. “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,” Rand said. “In solar cells, the light goes into a material, gets absorbed and creates heat. Here, we expect to have a very low heat load. Instead of the light being absorbed, energy is stored in the magnetic moment. Intense magnetization can be induced by intense light and then it is ultimately capable of providing a capacitive power source.”
What makes this possible is a previously undetected brand of “optical rectification,” says William Fisher, a doctoral student in applied physics. In traditional optical rectification, light’s electric field causes a charge separation, or a pulling apart of the positive and negative charges in a material. This sets up a voltage, similar to that in a battery. This electric effect had previously been detected only in crystalline materials that possessed a certain symmetry.
Rand and Fisher found that under the right circumstances and in other types of materials, the light’s magnetic field can also create optical rectification.
“It turns out that the magnetic field starts curving the electrons into a C-shape and they move forward a little each time,” Fisher said. “That C-shape of charge motion generates both an electric dipole and a magnetic dipole. If we can set up many of these in a row in a long fiber, we can make a huge voltage and by extracting that voltage, we can use it as a power source.”
The light must be shone through a material that does not conduct electricity, such as glass. And it must be focused to an intensity of 10 million watts per square centimeter. Sunlight isn’t this intense on its own, but new materials are being sought that would work at lower intensities, Fisher said.
“In our most recent paper, we show that incoherent light like sunlight is theoretically almost as effective in producing charge separation as laser light is,” Fisher said.
This new technique could make solar power cheaper, the researchers say. They predict that with improved materials they could achieve 10 percent efficiency in converting solar power to useable energy. That’s equivalent to today’s commercial-grade solar cells.
“To manufacture modern solar cells, you have to do extensive semiconductor processing,” Fisher said. “All we would need are lenses to focus the light and a fiber to guide it. Glass works for both. It’s already made in bulk, and it doesn’t require as much processing. Transparent ceramics might be even better.”
In experiments this summer, the researchers will work on harnessing this power with laser light, and then with sunlight.
The paper is titled “Optically-induced charge separation and terahertz emission in unbiased dielectrics.” The university is pursuing patent protection for the intellectual property.
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