Scientists created an ultra-thin dynamic amplifier for electromagnetic radiation using a parametric metasurface. A parametric metasurface is a thin composite material with a small-scale surface structure that changes periodically over time. The design provides extensive control over freely propagating input radiation, including amplifying up to 10 dB. Amplification is essential for long-distance transmission via air and space, such as in satellite and quantum communication.
The new design consists of an array of split-ring resonators with integrated variable capacitors called varactors, allowing high-frequency modulation. It is the first parametric amplification method used with free-space electromagnetic waves.
The parametric metasurface model was created by merging techniques from electronics and physics and applying them to electromagnetic modeling. The approach will operate for shorter wavelengths, but with the advancement of other ultrafast modulation technologies, it may be expanded into the infrared spectrum. Parametric amplification has a very low noise level and is used to amplify tiny signals in radio astronomy and quantum computing. An electric circuit must power each varactor in the array, and with advanced electronics, the phase of the varactors can be adjusted throughout the metasurface to influence the output. It enables numerous functionalities to be programmed into the same device, making beam steering and other forms of control valuable in communication applications.
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