EurekAlert August 17, 2020 An international team of researchers (UK, France, Italy) has spectroscopically observed bound electrons and holes, leading to the creation of an intraband bound exciton. The discrete resonance appears below the ionization threshold only when the coupling between light and matter is increased above a critical value. The result demonstrates that two charged particles can be bound by the exchange of transverse photons. Light–matter coupling can thus be used as a tool in quantum material engineering, tuning electronic properties of semiconductor heterostructures beyond those permitted by mere crystal structures, with direct applications to mid-infrared optoelectronics…read more. TECHNICAL […]
Category Archives: Light- matter interaction
Cartwheeling light reveals new optical phenomenon
Nanowerk June 29, 2020 While there are numerous forms of light polarization, only linear and circular polarizations, which have wave motion in a flat sheet or helix, respectively, are typically used. A team of researchers in the US (Rice University, UMass Dartmouth) utilized trochoidal polarizations with cartwheeling wave motion. They demonstrated that single gold nanorod dimers can discriminate between trochoidal fields rotating in opposite directions, which they named trochoidal dichroism. Trochoidal dichroism forms an additional classification of polarized light–matter interaction and could inspire the development of optical studies uniquely sensitive to molecules with cartwheeling charge motion, potentially relevant for probing […]
Electronics at the speed of light
EurekAlert December 23, 2019 The experimental set-up used by an international team of researchers (Germany, Spain, France, Luxembourg) involved nanoscale gold antennae as well as an ultrafast laser capable of emitting one hundred million single-cycle light pulses per second in order to generate a measurable current. The bowtie design of the optical antenna allowed for a sub-wavelength and sub-cycle spatio-temporal concentration of the electric field of the laser pulse into the gap of a width of six nm. As a result of the highly nonlinear character of electron tunneling out of the metal and acceleration over the gap in the […]
Scientists combine light and matter to make particles with new behaviors
Phys.org July 4, 2019 Researchers at University of Chicago developed techniques to manipulate quantum matter using Floquet engineering. By varying the intensity of a laser field tuned precisely to an atomic resonance, the team was able to shift the orbitals of an electron. Shaking the orbitals by periodically varying this intensity produced the desired copies. By allowing photons to interact with these shaken atoms, the team has created what they call “Floquet polaritons”—quasi-particles which are part-light and part-atom, and unlike regular photons, interact with each other quite strongly. These interactions are essential for making matter from light. Making polaritons with […]
Research on light-matter interaction could improve electronic and optoelectronic devices
Eurekalert October 10, 2018 To study low dimensional quantum materials and their quantum effects an international team of researchers (USA – Rensselaer Polytechnic Institute, Florida State University, UC Berkeley, Japan) built a device by stacking multiple atomically thin materials together, including graphene, boron nitride and tungsten diselenide. They showed that as the density of the exciton increases, more electrons and holes pair together, forming four-particle and even five-particle excitonic complexes. They revealed the true biexciton state, a unique four-particle complex responding to light and the nature of the charged biexciton, a five-particle complex. The research gives rise to fundamental understanding […]
Controlling photons with a photon
Phys.org June 28, 2018 To realize the strong light-matter interaction that is necessary for all-optical quantum devices, a team of researchers in the US (Harvard University, MIT) used a laser-cooled ensemble of 87Rb atoms (~10 uK) trapped within a high-finesse optical resonator (finesse ~50000) in an ultrahigh-vacuum chamber. To switch a photon with a photon in such a system, they used ‘vacuum-induced transparency’ in which an electromagnetic field as weak as a vacuum field is shown to alter the optical properties of atoms. The research is a step towards deterministic multi-mode entanglement generation as well as high-fidelity photonic quantum gates […]