Engineers from Harvard and Graz Universities of Technology have developed a metasurface for
Meta-optics is a silicon filmabout 200 nm thick, in which tiny holes are etched. The entire lens consists of hundreds of millions of holes with a diameter of 20 to 80 nm, with about 10 such holes made in each micrometer of the material. For comparison, the thickness of a human hair is 60 to 100 microns, and the diameter of a small virus is about 15 nm.
Extreme ultraviolet radiationhigh frequency and extremely short wavelength. This theoretically makes it possible to observe extremely small objects and fast processes in real time at a record spatial resolution. The problem is that most optical designs are opaque to such radiation.
In a metasurface, the lenses areholes. Their diameters differ and decrease from the center of the membrane outwards. Depending on the size of the hole, the light radiation falling there is distorted at different angles and, as a result, is focused to a point. Only the precise placement of the tiny holes allows this effect to be achieved.
The researchers tested the propertiesmetasurfaces in the experimental facility in Graz. The laser was focused on a jet of inert gas and generated extreme ultraviolet radiation in the form of very short pulses. The results of the study confirmed the possibility of using the lens to observe processes lasting several attoseconds (10–18 s). Physicists are currently working on a microscope that will use such optics.
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