New research numerically demonstrates how carefully structured materials can control light in ways that are both precise and robust. It brings together ideas from photonics and topology to show how a laser can emerge from the boundary between two distinct optical regimes. The physical system considered in the study is a bilayer photonic crystal. A […]
When we peel a crystal down to its very last layer, the physics governing its behavior undergoes a radical shift. This transition from the bulk (three-dimensional) to the two-dimensional limit is where some of the most exotic phenomena in condensed matter physics emerge. Among these, Titanium Diselenide, or TiSe₂, has long fascinated researchers because of […]
If you’ve ever sat by a quiet pond and tapped the surface of the water with your finger once every second, you’d expect to see a ripple travel outward once every second. In the world of classical physics, the effect follows the cause in a predictable, rhythmic march. But imagine for a moment that you […]
Order on a molecular scale is difficult to control. The systems with highest possible order are crystals, formed by long arrays of repeating constituent components in all directions. The most familiar examples of crystals encountered in daily life are table salt and sucrose, the sugar in our kitchens. Every grain of table salt is a […]
Light can do remarkable things, but it has limitations. Ordinary photons are bound by diffraction, which sets a limit on how tightly they can be confined in space. This is why focusing light to spots smaller than about half its wavelength is so difficult. But in certain materials, photons couple to vibrations of atoms or […]
Imagine a clock that doesn’t have electricity, but its hands and gears spin on their own for all eternity. In a new study, physicists at the University of Colorado Boulder have used liquid crystals, the same materials that are in your phone display, to create such a clock—or, at least, as close as humans can […]
A team of scientists has discovered a new type of crystal that can “breathe”—releasing and absorbing oxygen repeatedly at relatively low temperatures. This unique ability could transform the way we develop clean energy technologies, including fuel cells, energy-saving windows, and smart thermal devices. The newly developed material is a special kind of metal oxide made […]
When Georg Ohm wired up pieces of copper in 1827, he struck a rule so robust that it still underpins every phone and supercomputer on Earth: double the current, double the voltage. Simple, linear, universal—or so we thought. Over the past decade physicists have discovered that this bedrock principle crumbles the moment a crystal loses […]
Topological insulators are materials with special universal properties, which are protected against perturbations. Such properties are theoretically described by topology, a branch of mathematics concerned with the properties of geometrical objects that are unchanged by continuous deformations. Concretely, topological insulators are electronic materials that have a bulk band gap like an ordinary insulator but have […]
Liquid crystals are all around us, from cell phone screens and video game consoles to car dashboards and medical devices. Run an electric current through liquid crystal displays (LCDs) and they generate colours, thanks to the unique properties of these fluids: rearrange their shape, and they reflect different wavelengths of light. As the lab of […]