Needle light illuminates photonic processors

Scientists have discovered a new type of light beam, which propagates without spreading.The beam, which scientists dubbed “needle light” remains very narrow and precisely controlled.The needle of light extends for a distance great enough that it can be used inside chips that exchange data by light, so-called photonic processors .

Plasmonics

The needle of light is produced by a special class of quasiparticles called surface plasmons , electron waves traveling on a metal surface.The wires carrying these plasmons are seen as candidates to replace the copper wires that make the interconnections between the transistors inside the processors, consuming less energy and less warming.

One of the fundamental problems that have hindered the practical development of these plasmonic chips, is the fact that all waves spread laterally during propagation, a phenomenon known as diffraction.

This results in signal losses due to reduction of the signal which can be effectively detected.

Constructive Interference

Jiao Lin and Patrice Genevet demonstrated that the problem can be solved by carving a groove in a mesh metal film deposited on a glass plate.

When illuminated by a laser, the apparatus plasmônicas fires two waves that interfere with each other constructively, creating the beam non-difratante. The next step is to incorporate the component in an optical circuit to demonstrate its ability to transfer information efficiently.