Phys.org August 1, 2022 Light-matter interaction is well understood on the single-atom level and routinely used to manipulate atomic gases. However, in denser ensembles, collective effects emerge that are caused by light-induced dipole-dipole interactions and multiple photon scattering. An international team of researchers (Austria, Germany) found a mechanical deformation of a cloud of ultracold 87Rb atoms due to the collective interplay of the atoms and a homogenous light field. The collective light scattering results in a self-confining potential which exhibits nonlocal properties, attractive for both red- and blue-detuned light fields and induces a remarkably strong force that depends on the […]
Category Archives: Light- matter interaction
Atomically-smooth gold crystals help to compress light for nanophotonic applications
Phys.org July 13, 2022 An international team of researchers (South Korea, Denmark, Switzerland, Japan, USA – University of Minnesota) used a highly sensitive scanning near-field optical microscope (SNOM) to directly measure the optical fields of the hyperbolic image phonon-polaritons (HIP) propagating in a 63 nm-thick slab of hexagonal boron nitride (h-BN) on a monocrystalline gold substrate, showing the mid-infrared light waves in dielectric crystal compressed by a hundred times. They showed that the phonon-polaritons in van der Waals crystals can be significantly more compressed without sacrificing their lifetime. Practically zero surface scattering and extremely small ohmic loss in gold at […]
Nanoparticles control flow of light like road signs direct traffic
Science Daily June 20, 2022 An class of metasurface functionalities is associated with asymmetry in both the generation and transmission of light with respect to reversals of the positions of emitters and receivers. The nonlinear light–matter interaction in metasurfaces offers a promising pathway towards miniaturization of the asymmetric control of light. An international team of researchers (Germany, Australia, Singapore) has demonstrated asymmetric parametric generation of light in nonlinear metasurfaces by assembling dissimilar nonlinear dielectric resonators into translucent metasurfaces that produce images in the visible spectral range on being illuminated by infrared radiation. By design, the metasurfaces produce different and completely […]
It’s a trap! Laser light ensnared by invisible bonds
Science Daily June 1, 2022 Anderson localization predicts that transport in one-dimensional uncorrelated disordered systems comes to a complete halt, experiencing no transport whatsoever. However, a disordered physical system is always correlated because it must have a finite spectrum. Localization is dominant only for wave packets whose spectral extent resides within the region of the wave number span of the disorder. An international team of researchers (Israel, Germany, Spain) has experimentally shown that Anderson localization can occur and even be dominant for wave packets residing entirely outside the spectral extent of the disorder. The team studied the evolution of wave […]
Physicists discover light-induced mechanism for controlling ferroelectric polarization
Phys.org May 10, 2022 Ferroelectric materials exhibit ferroelectricity and the ability to polarize spontaneously. Typically, researchers can manipulate and reverse the polarization by the application of an external electric field. Ultrafast interactions between light and matter are another promising route for controlling ferroelectric polarization, but until now researchers have struggled to achieve a light-induced, deterministic control of such polarization. An international team of researchers (USA – University of Arkansas, France, Luxembourg) discovered a so-called “squeezing effect” in ferroelectric materials subject to femtosecond laser pulses. These pulses destroyed the polarization component that is parallel to the field’s direction and created polarization […]
High-Energy Interactions Between Light and Matter Described by Advanced New Mathematical Model
SciTech Daily March 15, 2022 High-harmonic generation has several applications, way to create table-top sources of extreme ultraviolet or x-ray light using lasers, and produce ultrashort light pulses, which are useful for imaging extremely rapid processes such as those that occur in atoms. But high-harmonic generation is inherently difficult to model mathematically, and understand fully. An international team of researchers (Japan, USA – University of Chicago) has developed an analytical approach to high-harmonic generation in the non-perturbative regime using mathematical techniques that had not previously been applied to high-harmonic generation. Their approach revealed the microscopic mechanism that converts incoming intense […]
Quantum information: Light from rare-earth molecules
Nanowerk March 11, 2022 Rare-earth ions (REIs) are promising solid-state systems for building light–matter interfaces at the quantum level. However, few crystalline materials have shown an environment quiet enough to fully exploit REI properties. Molecular systems can provide such capability but generally lack spin states and they show broad optical lines that severely limit optical-to-spin coherent interfacing. An international team of researchers (France, Germany) found that europium molecular crystals exhibit linewidths in the tens of kilohertz range, orders of magnitude narrower than those of other molecular systems. They harnessed this property to demonstrate efficient optical spin initialization, coherent storage of […]
Ultra-thin crystals as light sources in lasers
Nanowerk November 8, 2021 Previously an international team of researchers (Germany, Russia, USA – Arizona State University, Japan) reported that a layer of the semiconductor material molybdenum diselenide generated laser light at cryogenic temperatures. Now they created the same effect at room temperature in exciton-polaritons. If sufficient exciton-polaritons are generated, they merge into a macroscopic quantum state. A sudden increase in light emission from the sample indicates that this transformation has taken place. The resulting radiation has only a single wavelength and displays coherence. To demonstrate the effect, they placed thin layers of tungsten diselenide between special mirrors. By studying the […]
A highly simplified way to predict quantum light-matter interactions
Phys.org October 13, 2021 Calculating quantum light-matter takes enormous amounts of time and computing power—it also becomes very cumbersome. An international team of researchers (Germany, Sweden, Austria) has found a simple way to circumvent this problem by reshaping the equation so that the material part itself accounts for the quantum mechanical uncertainty of the light, far fewer additional photons are needed to describe the combined system of quantum light and matter. The new approach can capture most features of this extreme limit without the need to consider any photon at all. Adding just a few photons is enough to provide […]
Optically generated quantum fluids of light reveal exotic matter-wave states in condensed matter physics
Phys.org September 30, 2021 An international team of researchers (Russia, UK) used all-optical methods to create an artificial lattice whose nodes house polaritons called Lieb lattice, which usually does not occur in nature. Programmable spatial light modulator was used to shape a laser beam into a lattice inside the cavity. The generated polaritons both increased in number and became more energetic where the laser field was most intense and forming condensates at high enough laser power. The high-energy polariton waves escaped the condensates scattered and diffracted across the lattice. When the lattice constant was decreased, the condensates underwent a phase transition […]