An electric current can be visualized as a flow of electrons through a conducting piece of material. The less the resistance the material structure opposes to the flow of electrons the better a conductor it is. Part of this resistance appears at the surface, where electrons first encounter the material; as with electromagnetic radiation – […]
Future information and communication technologies will rely on the manipulation of not only electrons but also of light at the nanometer-scale. Squeezing light to such a small size has been a major goal in nanophotonics for many years. Particularly strong light squeezing can be achieved with polaritons, quasiparticles resulting from the strong coupling of photons […]
The magnitude of many of the exotic phenomena predicted for topological semimetals is directly proportional to something called the Chern number. Given the importance of the Chern number magnitude for these phenomena, it is just natural to wonder whether there is an upper limit for it and whether there are real materials in which this […]
No matter what you build or how much care you take building it, it would have defects. It seems it is a rule of nature: every time chaos gives way to order, from matter itself coming into existance in the very early universe to the formation of a crystal in a modern laboratory, defects appear […]
The concept of vector should be familiar: a quantity for which both magnitude and direction must be stated. This compares with a scalar quantity, where direction is not applicable, like temperature in a precise point. But, what if the magnitude varies with the direction? A vector would be a particular case, with only one direction […]
The Nobel Prize in Chemistry 2016 was awarded to Jean-Pierre Sauvage, Fraser Stoddart and Ben Feringa “for the design and synthesis of molecular machines”. Molecular machines are made by one or a few molecules linked together, comprising several hundred atoms. If a molecule can use an energy input to perform a mechanical movement (output) it […]
When we consider the variety of possible wonder applications of plasmonic nanoparticles we usually forget a key aspect: how these laboratory results can be transformed into something really usable in everyday life. For that to occur some not-that-simple problems must be resolved first. For example, plasmonic nanoparticles exhibit excellent light-harvesting properties in the visible spectral […]
One of the most mysterious features of quantum mechanics is that if two particles (or photons) interact at some point in time then the properties of these particles will remain connected at future times. A consequence of this is that determining the quantum state of one of the particles simultaneously determines the quantum state of […]
Condensed matter • Materials • Nanotechnology • Quantum physics • Theoretical physics
When two photons with the same energy interact with a nonlinear material, they “combine” and generate a new photon with twice the energy of the initial photons. More precisely, two photons at the fundamental frequency are absorbed by a plasmonic structure to emit one photon at the second-harmonic frequency. This is called second-harmonic generation. Second-harmonic […]
We all know what glass is, don’t we? We just point to the nearest window and it is that transparent sheet. Humans have been producing glass for at least 6,000 years, way before they knew how to smelt iron. Actually, the chemistry is well known: to produce window glass we just heat a mixture of […]