Researchers at nanoGUNE have discovered that infrared light can be transmitted and nanofocused using nano-sized transmission cables that feature two metal nanowires placed close together in a ladder structure. These cables steer the infrared light as a surface wave packed tightly together.
The research paper has been published in the April 3 issue of the journal Nature Photonics. The ladder structure when used at MHz frequencies delivers energy in waveguides of nanoscale diameter.
nanoGUNE's Transmission Lines
The team showed that infrared light can be transmitted by reducing the size of the cable to below 1micrometer. Two metal nanowires were developed and linked to an infrared antenna that absorbed infrared light and changed it into a surface wave along the cable. The width of the cable was gradually diminished, to compress the infrared surface wave to a nanospot at the taper apex measuring 60nm in diameter. The free-space wavelength is about 150 times bigger than the nanospot, revealing the subwavelength-scale focus derived. The team has developed a near-field microscopy method to identify multiple electrical field units with nanoscale resolution.
A cable linked to the antenna, helps the light absorbed by the nanoantenna to be transmitted over long distances and nanofocused in a distant spot. Rainer Hillenbrand, who led the Nanooptics Group said this discovery proved that the idea of classical radiofrequency can be applied at infrared frequencies. Martin Schnell, who did the clinical testing, says this frequency is 30THz.
Source: http://www.nanogune.eu/