Since its origin about 75 years ago, electronics has grown faster than any other major engineering discipline. Electronics is one of the technologies being created today which is widely used all over the world. In fact, all of our gadgets and machines like computers and televisions are being generated with electronics. Therefore, without this, we cannot enjoy using the inventions that we have around us. The four basic elements of electronics are: electrons as carrier vectors, electrical cables and circuits, the generators and transistors.
Analysis of the essential characteristics of electronics leads to the conclusion that the normal growth-limiting mechanisms are not operative in this area. The commitment of electronics to information handling is stipulated and it is concluded that electronic information processing is a new milestone in a field that is vital for human survival. Though growth in electronics is open-ended, as in other engineering branches, developments within the field are subject to recognizable constraints. These constraints are being identified/classified and most of them turn out to be relative and sliding with the progress of time. The consequences of changing patterns of constraints are illustrated on past developments and their possible impact on future trends is brought forward.
Electronics at the speed of light
Currently, most of our data travels through either copper wire or fiber optic cable. Even when we send data via our cell phones over radio waves, which also travel at light speed, it ends up traversing the wired networks of the Internet at some point. The two most common types of copper wire for long-distance information transfer are twisted pair (used first for telephony, and later for dial-up Internet and Digital Subscriber Line, DSL), and coaxial cable (used for cable TV initially, then Internet and phone). Coaxial cable is the faster of the two. But still faster is fiber optic cable. Rather than using copper to conduct data in the form of electrical signals, fiber optic cable moves data as pulses of light. Motion of electrons (Electronics) in metallic wires (like copper) limit the speed of electrons due to relativistic effects and also ohmic losses (generation of heat on passing a current through a conductor due to its resistance) and other losses. There have been recent breakthroughs in transferring data over copper wiring at nearly fiber optic speeds via reducing interference and other techniques. Researchers are also working on transmitting data via light through the air using lightbulbs for WiFi, or transmitting laser beams from building to building. Again, light through the air does move at close to light speed, but nothing we have now is surpassing the speed limit. Therefore, can we achieve actual faster-than-light transfer of data and here are some developments in this regard.
- Fiber optic cable is still far faster than copper wire, and isn’t as susceptible to electromagnetic interference. Fiber can achieve speeds of hundreds of Gigabits per second, or even Terabits. Home Internet connections don’t achieve those super high speeds, at least partially because wiring is being shared by many households over entire areas, and even networks that use fiber optics generally have copper running the last stretch into people’s homes. But with fiber running all the way to neighborhood or home, one can get something in the range of 50 to 100 Megabits per second of data transfer, compared to 1 to 6 Megabits per second from average DSL lines and 25 or so Megabits per second from cable. Actual data speeds vary greatly by location, provider and chosen plan, of course. Light has the maximum and constant speed of 3×108 m/s in vacuum. Light through fiber optic is not as fast as light through a vacuum. Light, when moving through just about any medium, is slower than the universal constant we know as the speed of light. The difference is negligible through air, but light can be slowed down considerably through other media, including glass, which makes up the core of most fiber optic cabling. The refractive index of a medium is the speed of light in a vacuum divided by the speed of light in the medium. Some fiber optic cabling is made of plastic, which has an even higher refractive index, and therefore a lower speed. Part of the reason for the decrease in speed is the dual nature of light. It has the attributes of both a particle and a wave. Light is actually made up of particles called photons, and they do not move in a straight line through the cabling. As the photons hit molecules of material, they bounce in various directions. Light refraction and absorption by the medium eventually lead to some energy and data loss. This is why a signal can’t travel indefinitely and has to be boosted periodically to cover long distances. However, the slowing of light isn’t all bad news. Some impurities are added to fiber optics to control the speed and aid in channeling the signal effectively.
- Scientists at the National Institute of Standards and Technology (USA) are claiming to have achieved faster-than-light transfer of quantum data using something called four-wave mixing, which incidentally is a phenomenon that’s considered a form of interference infiber optic The experiment involves sending a short 200-nanosecond seed pulse through heated rubidium vapor and at the same time sending in a second pump beam at a different frequency to amplify the seed pulse. Photons from both beams interact with the vapor in a way that generates a third beam. Apparently, the peaks of both the amplified seed pulse and the newly generated pulse can exit faster than a reference beam traveling at the speed of light in a vacuum. The speed differences they reported were 50 to 90 nanoseconds faster than light through a vacuum. They even proclaimed being able to tune the speed of the pulses by altering the input seed detuning and power.
- Another fast data transfer technology in the works is quantumteleportation, which relies on the existence of entangled pairs: two particles that are in tune with each other to the point that if we measure one, the other ends up with the same quality that found in the first one, no matter their distance from one another. This also requires a third particle that contains the actual bits of data we are trying to transfer. A laser is used to teleport one of the entangled particles elsewhere, in a manner of speaking. It isn’t really transporting a photon, but rather changing a new photon into a copy of the original. The photon in the entangled pair can be compared to the third photon to find their similarities or differences, and that information can be relayed to the other location and used for comparison with the twin particle to glean the data. This sounds like something that would result in instant transfer, but that’s not the case. Laser beams only travel at the speed of light. But this has potential applications for sending encrypted data via satellite, and for networking quantum computers, should we ever invent them. And it’s further along than any attempts at superluminal data transfer. It works over miles at this point, and researchers are trying to increase the teleportation distance.
- Physicists have fabricated new two-dimensional quantum materials with breakthrough electrical and magnetic attributes that could make them building blocks of future quantum computers and other advanced electronics. Researchers explored the physics behind the 2-D states of novel materials and determined they could push computers to new heights of speed and power. The research is conducted at extremely cold temperatures and that the signal carriers in are not electrons — as with traditional silicon-based technologies — but Dirac or Majorana fermions, particles without mass that move at nearly the speed of light. The signal carriers in this 2-D superconductor are Majorana fermions, which could be used for a braiding operation that theorists believe is vital to quantum computing.
- Other researchers have taken the first definitive step to produce high-speed electronic devices that can operate one million times faster than modern electronics. At the Max Planck Institute of Quantum Optics in Garching, Germany, researchers used laser light to generate very high frequency electric current inside a solid material. The electrons were found to be moving at a speed (frequency) close to 1015(one million billion) hertz; the best achievable speed in modern transistors is only 109 (one billion) hertz. Conventionally, the motion of electrons (conductivity) is achieved by applying voltage but researchers controlled the motion of electrons inside the solid material by using laser pulses. Light waves are electromagnetic in nature and have very high oscillation frequency of electric and magnetic fields. This ultra-high frequency of light waves can be used to drive and control electron motion in semiconductors. Electronics, when driven by such light waves, will be inherently faster than current state of electronics. When we shine high-intensity laser on silicon dioxide, nanofilm electrons are generated. When the electrons move in the presence of electric field of the laser, it generates current. Initially, the nanofilm behaves like an insulator, but when we shine high-intensity laser, it behaves like a conductor. The conductivity increases by more than 19 orders of magnitude in the presence of laser pulse. The performance of high-speed circuits rely on how quickly electric current can be turned on and off inside a material. They showed that you could turn the conductivity of silicon dioxide nanofilm from zero to very high values in a time interval of 30 attoseconds, which is one million times faster than modern electronics. The very short time interval needed to turn silicon dioxide from an insulator to a conductor was possible as the team used high-intensity and extremely short laser pulses and silicon dioxide in the form of a nanofilm. In the bulk form, silicon dioxide tends to get damaged by high-intensity laser as the material tends to accumulate heat produced by the laser pulse. But as a nanofilm, silicon dioxide becomes nearly transparent to laser and absorbs less heat and therefore gets less damaged.
Other forms of electronics
There is nothing around us faster than light and by creating electronic components at nano level that work with light instead of electric current, we can create electronics at the speed of light. Progress in photonics provides the opportunity to replace electron flow, for transmission and computing, with a photonic flow or a plasmonic flow; harnessing the interaction between the surface electrons of nanostructured circuits and photons. The information carrier vectors in photonics can be photons, solitons, light balls, or plasmons. The plasmon is a quasi-particle associated with the plasma oscillations of free electron density. Plasmonics is a new device technology that exploits the unique optical properties of nanoscale metallic structures to route and manipulate light at the nanoscale. The association of this particle, resulting from existing electrons present in the material and injected photons, offers at least two, unique, highly important benefits: the possibility to transmit information with higher frequency (about ∼100 THz) and the ability to confine light in very small dimension objects. Lasers and spasers are the optical equivalent of electrical generators; optical wave guides and optical fibers act as the transport cables; and plasmonsters and optical transistors are the equivalents of electrical switches and electronic transistors. These new photonic structures are very similar to those found in electronics. Electronics has also inspired photonics for optical circuits, and by combining these two sciences, plasmonics circuits have been realized in the last few years. By comparing the basic elements from these two sciences – the electron in electronics vs the photon, soliton and plasmon in photonics it can be said that photonics has built up, step by step, all the tools already available in electronics. These similarities lead to the idea that, in the future, we may be able to replace devices that use an electronic flow (mobile phones, computers, displays, etc.) with equivalent devices that use a photonic or a plasmonic flow. Furthermore, in the case of a photonic flow, it may be possible to take advantage of the ultimate photon generator ‘the Sun’ as a power source. Indeed, optical fiber networks are already in place and could represent a first step in connecting future plasmonic computers.
While current electronics and photonics are based on silicon and silicon dioxide, carbon, in both bulk and graphene form, might be the future element of choice. Graphene is a very interesting material for electronic applications, as a transparent electrode with very good mechanical properties, with new transfer techniques allowing deposition on large area flexible surfaces. Due to the absence of an optical band gap, graphene absorbs all photons at any wavelength. However, if incident light intensity becomes strong enough, due to the Pauli blocking principle, the generated carriers fill the valence bands, preventing further excitation of electrons at valance band. Hence this property could potentially be exploited to realize short and very intense light pulses lasers with a wide optical response ranging through ultra-violet, visible, infrared to terahertz. These lasers might be the future of pulsed signal photonic generators. Moreover, graphene’s structure specificity and charge transport properties open up new research possibilities through graphene nanoplasmonics. Today we transform different forms of energy into electricity to meet most of our needs. But, will it be possible to avoid the transformation of the energy in electricity and directly exploit solar energy for all our requirements. For heating, we can and often do already use solar energy directly, without transforming it. If light storage is possible through plasmons, laser cavities, or light trapping as in the black body model, it will be possible to directly use solar energy for lighting too. Optical manipulation and optical engine concepts have already been experimentally demonstrated, and the progress in photonics with optical circuits, optical transistors, etc.
has shown that photonic or plasmonic informatics might be possible too. If laser propulsion can be achieved, and optical engines work, we may also have motors working with light.
We can be sure that if the speed of light is broken, we’ll be applying it to our Internet transmissions far sooner than to interstellar travel. Our ability to watch the highest quality television and surf the net at the fastest speeds will be paramount. And perhaps for those purposes, even getting ourselves to truly as-fast-as-light transmission would do wonders. The answer to whether meaningful information can travel faster than light is currently no. We’re only at the level of moving a few quantum particles at speeds that may possibly be over the speed of light, if the data pans out on subsequent experiments. To have a practically applicable form of data transfer, we have to be able to send organized bits of data that mean something, uncorrupted, to another machine that can interpret it. The fastest transmission in the world will mean nothing otherwise.
Dr. S. S. Verma, Department of Physics, S.L.I.E.T., Longowal, Distt.-Sangrur (Punjab)-148106.