Nanowerk November 29, 2022 Harnessing the full complexity of optical fields requires the complete control of all degrees of freedom within a region of space and time. An international team of researchers (USA – MIT, industry, State University of New York, Rochester Institute of Technology, ARL (Rome), UK, Canada) resolved this challenge with a programmable photonic crystal cavity array enabled by four key advances: (1) near-unity vertical coupling to high-finesse microcavities through inverse design; (2) scalable fabrication by optimized 300 mm full-wafer processing; (3) picometre-precision resonance alignment using automated, closed-loop ‘holographic trimming’; and (4) out-of-plane cavity control via a high-speed μLED […]
Tag Archives: Light
Transporting of two-photon quantum states of light through a phase-separated Anderson localization optical fiber
Phys.org November 23, 2022 Experiments in the past have demonstrated Anderson localization in optical fibers, classical or conventional light, in two dimensions while propagating it through the third dimension. An international team of researchers (Spain, USA – industry, Italy) engineered the optical setup to send the quantum light through the phase-separated Anderson localization fiber and detected its arrival with the single-photon avalanche diode (SPAD) array camera. It enabled them not only to detect and identify them as pairs, as they arrived at the same time. As the pairs are quantum correlated, knowing where one of the two photons is detected […]
When light and electrons spin together
Phys.org July 12, 2022 An international team of researchers (Germany, Spain, USA – research organization) has demonstrated how the coupling between intense lasers, the motion of electrons, and their spin influences the emission of light on the ultrafast timescale. They demonstrated how changes in the electron velocity can affect the electron dynamics in Na3Bi and that this effect can sometimes be detrimental to the generation of high-order harmonics. While this material is non-magnetic, the team has shown that the spin of the electrons is important for the dynamics, as it couples to the potential felt by the electrons, which is […]
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 […]
A nanoscale 3D structure to control light
Phys.org February 2, 2022 Metamaterials can be engineered to produce desired interactions with light or sound waves. However, functionality of the devices can be limited by the corresponding design space. A team of researchers in the US (Pennsylvania State University, Sandia National Laboratory) leveraged a combination of a genetic algorithm (GA) based optimization method and a membrane projection lithography (MPL) fabrication approach, to demonstrate a quasi-3D metamaterial for broadband asymmetric transmission (AT) of linearly polarized mid-infrared light. An efficient exploration of 3D plasmonic meta-atoms with broken mirror symmetry in the light propagation direction allows the satisfaction of the rigorous conditions […]
Physicists manipulate magnetism with light
Nanowerk January 28, 2022 The non-equilibrium driving of dressed quasiparticles offers a promising platform for realizing unconventional many-body phenomena and phases beyond thermodynamic equilibrium. An international team of researchers (USA – MIT, South Korea) achieved this in the van der Waals correlated insulator NiPS3 by photoexciting its newly discovered spin–orbit-entangled excitons that arise from Zhang-Rice states. By monitoring the time evolution of the terahertz conductivity, they observed the coexistence of itinerant carriers produced by exciton dissociation and a long-wavelength antiferromagnetic magnon that coherently processes in time. These results demonstrate the emergence of a transient metallic state that preserves long-range antiferromagnetism, […]
The perfect trap: a new way to control the polarization of light
Phys.org January 19, 2022 An international team of researchers (Germany, UK, Scotland, Switzerland) has demonstrated that the Kerr effect in a high-finesse Fabry-Pérot resonator can be utilized to control the polarization of a continuous wave laser. They showed that a linearly polarized input field is converted into a left- or right-circularly-polarized field, controlled via the optical power. The observations are explained by Kerr-nonlinearity induced symmetry breaking, which splits the resonance frequencies of degenerate modes with opposite polarization handedness in an otherwise symmetric resonator. According to the researchers in the future one could arrange many of these devices onto a photonic […]
A quantum view of ‘combs’ of light
Phys.org December 16, 2021 An international team of researchers (USA – Stanford University, Germany) used second-order photon correlations to study the underlying quantum processes of soliton microcombs in an integrated silicon carbide microresonator. They showed that a stable temporal lattice of solitons can isolate a multimode below-threshold Gaussian state from any admixture of coherent light and predict that all-to-all entanglement can be realized for the state. Their work opens a pathway toward a soliton-based multimode quantum resource. Microcombs have the potential to enhance countless technologies, including GPS systems, telecommunications, autonomous vehicles, greenhouse gas tracking, spacecraft autonomy and ultra-precise timekeeping…read more. […]
Getting quantum dots to stop blinking
Science Daily November 22, 2021 Quantum dots tendency to blink off at random intervals has hampered its use for biochemical applications. Researchers at MIT have come up with a way to control this unwanted blinking by firing a beam of mid-infrared laser light for an infinitesimal moment which eliminates the quantum dot’s blinking for a relatively long period. According to the researchers the cause of the blinking phenomenon probably has to do with extra electrical charges, such as extra electrons, attaching to the outer part of the quantum dots, altering the surface properties providing alternative pathways for the extra energy […]