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Smallest laser pins down light

作者:谷庀    发布时间:2019-03-03 01:07:05    

This diminutive drawing pin, which is only a five-hundredth of a millimetre in diameter, is claimed by its developers to be the world’s smallest laser. The disc at the top is only 400 atoms thick and is a sandwich of indium gallium arsenide between layers of similar material which also contain phosphorus. Sam McCall of AT&T Bell Laboratories in New Jersey laid down the layers by spraying the surface of a substrate with a beam of molecules containing the required constituents, which settle into thin layers on the surface. The region of the surface required for the disc is then covered with a protective layer and the rest of the surface and the substrate beneath are etched away with chemicals. The point of the pin connects it to the remaining substrate. Unlike in most lasers, where light bounces back and forth between opposite faces, light in the disc travels around the perimeter,

 

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