Fluxon based superconducting electronics

In superconductors, there exist vortices invisible to the human eye. These are vortices of electric current that swirl like miniature hurricanes. Although, their size may not exceed a biological cell, onset of such miniature hurricanes is damaging for superconductivity, just like usual hurricanes in the atmosphere. Luckily, unlike these monsters, Josephson vortices are tame and easy to restrain. Vortices can be trapped between two superconducting plates and may never leave the system, except through a boundary. In this way, we may compel them to generate Terahertz waves needed for medical screening, use for transmission of information and even utilize in future digital electronics. Josephson vortices exist on the border of two superconducting metals separated by a thin insulating layer -- sandwiches called Josephson junctions. The electrical current flowing through the junction may generate vortices similar to hurricanes seen in nature. Each vortex consists of magnetic flux trapped by electrons whirling around. Sometimes Josephson vortices are called fluxons. Fluxons may travel faster-than-light and possess many intriguing properties of interest to the scientific community. Recently we have demonstrated that a single vortex can be cloned / cut in pieces, each representing an individual vortex (Phys. Rev. Lett. 97, 017004). This phenomenon has no analogy in conventional electronics or engineering sciences, but the closest analogy, surprisingly, comes from biology. The vortex is cloned in the same way a biological cell reproduces itself. The effect allows constructing novel devices that have never existed before. The new devices fall into three themes of the proposed project: (i) Effective sources of Terahertz radiation (ii) Digital superconducting electronics (iii) Magnetic sensors.Theme (i) is devoted to the question as how to generate Terahertz (THz) waves utilizing the recently discovered properties of fluxons. Currently there is a great need for reliable sources of THz radiation. This is an unexplored region of the electromagnetic spectrum with wavelengths between 30 micron and 1 mm. Similar to X-rays, THz waves may penetrate bodies, clothes, packaging and even walls. However, because of their non-ionizing properties, Terahertz waves are harmless to living organisms, unlike X-rays. This is very important for building new types of absolutely safe and non-invasive imaging systems for medical diagnostics, health monitoring and security screening. Because plastics and cardboard are transparent to terahertz radiation, it can be also used for quality control and inspection of packaged objects. Among other applications are astronomical instruments, environmental monitoring, telecommunications, biological and chemical identification.Theme (ii) is focused on digital applications. As Josephson vortices may propagate at the speed of light, they can be effectively used to transmit and process information. Electronic components made of superconductors offer great benefit compared to semiconductor counterparts. Indeed, with the use of superconductors one can achieve very small energy losses, low power consumption and reduced noise. Novel superconducting electronics can be integrated in modern supercomputers that will be utilized for solving all kinds of actual scientific problems. Theme (iii) is devoted to development of novel magnetic sensors. First of all, new magnetometers can be utilized for medical purposes. They are expected to be more efficient than contemporary SQUID magnetometers because of their fast operation.