The movement direction of the surface plasmon waves, which are used in optical microcomputers for transmitting information signal can be controlled by using dielectric nanoparticles. Using this effect, scientists at the University ITMO was able to develop a demultiplexer with a spectral resolution of 10 nanometers. The work is published in Laser & Photonics Review.
The idea is to use light pulses to transmit information has been used effectively, for example, is based on the principle of operation of fiber-optic cable. But in order to use it for work photon computer that you want to make fit on a microchip, use the pulses of light is not obtained because of too large length of a wave. To solve this problem, scientists propose to convert the light wave into surface plasmon polaritons — quasiparticles, which represent the resonance frequencies of the electrons in the surface layer of the material, which are excited by an external electromagnetic field and distributed along the surface of the material. However, their use is already complicated due to the lack of methods to control their motion depending on the frequency.
In their new study, a team of physicists from the University ITMO has proposed to use to control the movement of surface waves and dielectric nanoparticles. In fact, each particle consists of nanoantenna that can take an optical signal in the visible range. If you put it on a gold substrate, then taking the incoming signal, it will initiate in the substrate is necessary ñ surface plasmon.
The resulting quasi-particle has a magnetic response, so the direction of its movement can be controlled using polarized light. So, if nanoantenna accepts a p-polarized signal in which the plane of incidence coincides with the direction of the electric field, it is excited with three independent dipole moment: magnetic dipole moment along one of the axes, and two electric dipole moment along the other two axes. The interaction of these dipole moments will launch surface plasmon polariton in one direction. The direction is dependent on the wavelength of the received signal.