04-05-2016, 11:40 AM
An optical antenna is a device that efficiently couples the energy of free-space radiation to a confined region of subwavelength size. While antennas are widespread in the radiowave and microwave regimes they are basically unexplored at optical frequencies. Because nanoscale devices need to interface with optical radiation it is likely that optical antennas will have a broad impact on future technology.
Why Optical Antennas?
The concept of antennas is not new, by any means. They are the enabling technology in cellular phones, satellite communication, and many other devices which use electromagnetic radiation. However, their optical counterpart is basically non-existent in today's technology. Instead, optical radiation is manipulated by redirecting the wavefronts with lenses and mirrors. Consequently, because of diffraction, it appears that optical fields cannot be localized to dimensions much smaller than the optical wavelength. Optical antennas are a solution to the mismatch between the small dimensions of nanoscale devices and the length scale associated with optical wavelengths. It can be expected that optical antennas will be used for artificially enhancing the absorption cross-section or quantum yield of optoelectronic devices (e.g. solar cells), for efficiently releasing energy from nanoscale devices (e.g. LED lighting), and for boosting the efficiency of biochemical detectors relying on a distinct spectroscopic response (Raman scattering, fluorescence, etc. ).
Why Optical Antennas?
The concept of antennas is not new, by any means. They are the enabling technology in cellular phones, satellite communication, and many other devices which use electromagnetic radiation. However, their optical counterpart is basically non-existent in today's technology. Instead, optical radiation is manipulated by redirecting the wavefronts with lenses and mirrors. Consequently, because of diffraction, it appears that optical fields cannot be localized to dimensions much smaller than the optical wavelength. Optical antennas are a solution to the mismatch between the small dimensions of nanoscale devices and the length scale associated with optical wavelengths. It can be expected that optical antennas will be used for artificially enhancing the absorption cross-section or quantum yield of optoelectronic devices (e.g. solar cells), for efficiently releasing energy from nanoscale devices (e.g. LED lighting), and for boosting the efficiency of biochemical detectors relying on a distinct spectroscopic response (Raman scattering, fluorescence, etc. ).