“Device” is a disc 250 nm in diameter that is capable of switching optical pulses at femtosecond rates (femtosecond is a one millionth of one billionth of a second). Credit: Maxim Scherbakov et al
Researchers developed an ultrafast all-optical switch based on nonlinear dielectric silicon nanostructures. The operation of the switching is based on the interaction between 2 femtosecond pulses; at the same time, the undesirable free-carrier effects are suppressed. Ultrafast optical switching will permit to create data transmission and processing devices which will handle speeds high enough to download 1000s of HD-movies/sec.
Photons address the data transmission problem better than electrons. This property can primarily be used for in computing where IPS (instructions/sec) is the main attribute to be maximized. The typical scale of eletronic transistors- the basis of contemporary electronic devices -is <100 nm’s, wheres the typical scale of photonic transistors stays on the scale of several micrometers. Nanostructures that are able to compete with the electronic structures, eg, plasmonic nanoparticles are characterized by low efficiency and significant losses. Thus, coming up with a compact photonic switch was a challenging task.
3 yrs ago several groups of researchers simultaneously discovered an important effect: they found out that silicon nanoparticles are exhibit strong resonances in the visible spectrum – the so-called magnetic dipole resonances. This type of resonance is characterized by strong localization of light waves on subwavelength scales, inside the nanoparticles.
Nanoparticles were fabricated in the ANU by e-beam lithography followed by plasma-phase etching. Eventually, researches developed a “device”: a disc 250 nm in diameter capable of switching optical pulses at femtosecond rates. Switching speeds that fast will allow to create data transmission and processing devices that will work at tens and hundreds terabits per second. This can make possible downloading thousands of HD-movies in less than a second.
The operation of the all-optical switch created by MSU is based on the interaction between 2 femtosecond pulses, due to magnetic resonance of the silicon nanostructures. If the pulses arrive at the nanostructure simultaneously, one of them interacts with the other and dampers it due to the effect of 2-photon absorption. If there is a 100-fs delay between the 2 pulses, the interaction does not occur, and the second pulse goes through the nanostructure without changing.
“We were able to develop a structure with the undesirable free-carrier effects are suppressed, Free carriers (electrons and electron holes) place serious restrictions on the speed of signal conversion in the traditional integrated photonics. Our work represents an important step towards novel and efficient active photonic devices- transistors, logic units, and others. Features of the technology implemented in our work will allow its use in silicon photonics. In the nearest future, we are going to test such nanoparticles in integrated circuits.”
http://www.eurekalert.org/pub_releases/2015-10/lmsu-twf102715.php
Recent Comments