New type of metasurface with adjustable beam frequency and direction

Recently, according to the journal Nature Nanotechnology, a team from the California Institute of Technology reported that they have constructed a metasurface covered with micro adjustable antennas that can reflect incident light beams: one beam of light enters and multiple beams of light exit, each with a different frequency and propagating in a different direction. This is a new method for processing free space signals rather than fiber optic signals, which can create many sidebands or channels with different optical frequencies.

When many people share the same Wi Fi network, the network may experience latency or lag. But if everyone had a dedicated wireless communication channel, it would be hundreds of times faster and bandwidth increased than the Wi Fi we use today. The new research is not only expected to be used for developing new wireless communication channels, but also opens up new avenues for developing new ranging technologies or transmitting large amounts of data into space.

Researchers have constructed a metasurface covered with micro adjustable antennas that can reflect incident light beams, creating many sidebands or channels of different optical frequencies.

The research team stated that the design of metasurfaces aims to surpass the effects that traditional optical components such as cameras or microscope lenses can achieve. This multi-layer crystal tube like device is called a "spatiotemporal metasurface", which adopts carefully selected nanoscale antenna pattern design to change the response of light, and can reflect, scatter or otherwise control light, such as reflecting light in a specific direction and at a specific frequency.

The core width and length of the device are both 120 microns, and the wavelength of the light wave used when operating in reflection mode at the optical frequency is 1530 nanometers, which is thousands of times higher than the frequency of radio waves, meaning that the available bandwidth is much larger.

The research team suggests that these metasurfaces could be used in the field of LiDAR, where light can be used to capture depth information of three-dimensional scenes. The ultimate goal of the team is to develop a 'universal metasurface' that can create multiple optical channels in free space, with each channel transmitting information in a different direction. They envision that in the future, when many people use laptops in the same coffee shop, everyone will no longer receive wireless Wi Fi signals, but instead receive their own high fidelity beam signals, and no longer have to worry about internet speed issues.

Source: Science and Technology Daily