| 摘要 |
A light-activated reflector having a plurality of coplanar arrays of parallel optical fibers that are each covered with a thin coating of a semiconductor material. Silicon, germanium, and indium antimonide, for example, along with other suitable materials, may be used as the coating of semiconductor material. The number and spacing of the coplanar arrays are determined by the shortest wavelength at which the reflector is to be operated. Electron-hole pairs are created in the coating of semiconductor material when it is illuminated by photons having energy greater than the band-gap energy of the semiconductor material. Light is injected into the optical fibers of a selected array. The injected light is absorbed and creates electron-hole pairs in the coating of semiconductor material, which modifies the permittivity of the coating. The absorbed light causes the coating to become reflective at millimeter wave frequencies. A collimated millimeter-wave beam incident on the light-activated coplanar array is reflected at an angle equal to the angle of incidence. The millimeter-wave beam may be steered to a different angle by appropriately activating light sources associated with a different array of optical fibers.
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