The Anderson transition is a phase transition that occurs in disordered systems, which entails a shift from a diffusive state (i.e., in which waves or particles are spread out) to a localized state, in which they are trapped in specific regions. This state was first...
Optics & Photonics
A promising technique to steer laser-produced THz radiation in air
Terahertz radiation (THz), electromagnetic radiation with frequencies ranging from 0.1 and 10 THz, is central to the functioning of various technologies, including imaging, sensing and spectroscopy tools. While THz radiation waves have been manipulated in different...
Coupled semiconductor lasers generate novel optical patterns, enabling new spectroscopy techniques
The physical interaction between two or more systems, also known as coupling, can give rise to unique and unexpected effects. In the field of optics, coupled light sources (e.g., lasers) can influence each other, producing complex light patterns that cannot be emitted...
Compact on-chip polarimeter measures light polarization with high accuracy
Reliably measuring the polarization state of light is crucial for various technological applications, ranging from optical communication to biomedical imaging. Yet conventional polarimeters are made of bulky components, which makes them difficult to reduce in size and...
Optical spring enables programmable defect mode in new mechanical crystal
Mechanical crystals, also known as phononic crystals, are materials that can control the propagation of vibrations or sound waves, just like photonic crystals control the flow of light. The introduction of defects in these crystals (i.e., intentional disruptions in...
Observing gain-induced group delay between multiphoton pulses generated in a spontaneous down-conversion source
Spontaneous parametric down-conversion (SPDC) and spontaneous four-wave mixing are powerful nonlinear optical processes that can produce multi-photon beams of light with unique quantum properties. These processes could be leveraged to create various quantum...
A versatile approach to realize quantum-enhanced metrology with large Fock states
New Sisyphus cooling technique could enhance precision of atomic clocks
Researchers in the Neutral Atom Optical Clocks Group at the National Institute of Standards and Technology (NIST), University of Colorado and Pennsylvania State University recently devised a new sub-recoil Sisyphus cooling technique that could help to improve the...
A mechanism that transfers energy from nitrogen to argon enables bidirectional cascaded lasing in atmospheric air
To produce light, lasers typically rely on optical cavities, pairs of mirrors facing each other that amplify light by bouncing it back and forth. Recently, some physicists have been investigating the generation of "laser light" in open air without the use of optical...
The design of a photonic alloy with topological properties
Photonic alloys, alloy-like materials combining two or more photonic crystals, are promising candidates for the development of structures that control the propagation of electromagnetic waves, also known as waveguides. Despite their potential, these materials...