Amazing stuff! My apologies, this research is a bit dated!
"... The surface can be reconfigured up to millions of times per second to change how it is locally controlling light. That’s rapid enough to manipulate and redirect light for applications in optical data transmission such as optical space communications and Li-Fi, as well as lidar. ...
By contrast, the new work offers the prospect of electrically manipulating a material’s optical properties via a semiconducting material. Combined with nano-scaled mirror elements, the flat, microscopic devices can be made to behave like a lens, without requiring lengths of curved or bent glass. And the new metasurface’s optical properties can be switched millions of times per second using electrical signals. ...
The device itself, a chip that measures 120 micrometers on each side, achieves its light-manipulating capabilities with an embedded surface of tiny gold antennas in a semiconductor layer of indium tin oxide. Manipulating the voltages across the semiconductor alters the material’s capacity to bend light—also known as its index of refraction. ..."
The device itself, a chip that measures 120 micrometers on each side, achieves its light-manipulating capabilities with an embedded surface of tiny gold antennas in a semiconductor layer of indium tin oxide. Manipulating the voltages across the semiconductor alters the material’s capacity to bend light—also known as its index of refraction. ..."
"In a paper ... reports building such a metasurface patterned with miniscule tunable antennas capable of reflecting an incoming beam of optical light to create many sidebands, or channels, of different optical frequencies. ...
"It's acting like an entire array of communication channels. And we've found a way to do this for free-space signals rather than signals carried on an optical fiber." ...
"It's acting like an entire array of communication channels. And we've found a way to do this for free-space signals rather than signals carried on an optical fiber." ...
The work points to a promising route for the development of not only a new type of wireless communication channel but also potentially new range-finding technologies and even a novel way to relay larger amounts of data to and from space. ..."
From the abstract:
"Active metasurfaces enable dynamic manipulation of the scattered electromagnetic wavefront by spatially varying the phase and amplitude across arrays of subwavelength scatterers, imparting momentum to outgoing light. Similarly, periodic temporal modulation of active metasurfaces allows for manipulation of the output frequency of light. Here we combine spatial and temporal modulation in electrically modulated reflective metasurfaces operating at 1,530 nm to generate and diffract a spectrum of sidebands at megahertz frequencies. Temporal modulation with tailored waveforms enables the design of a spectrum of sidebands. By impressing a spatial phase gradient on the metasurface, we can diffract selected combinations of sideband frequencies. Combining active temporal and spatial variation can enable unique optical functions, such as frequency mixing, harmonic beam steering or shaping, and breaking of Lorentz reciprocity."
Nanoscale Device Simultaneously Steers and Shifts Frequency of Optical Light, Pointing the Way to Future Wireless Communication Channels (original news release)
Electrically tunable space–time metasurfaces at optical frequencies (no public access)
An incident laser beam (green) hits ... new space-time metasurface and gets modulated by tunable, nanostructured antennas, creating steerable beams of light at different frequencies (blue) that could be used as optical channels for transmitting data on Earth or in space.
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