Phys.org April 15, 2024 An international team of researchers (Denmark, Croatia) demonstrated a memory for light based on optomechanically induced transparency. They achieved a long storage time by leveraging the ultralow dissipation of a soft-clamped mechanical membrane resonator, which oscillated at MHz frequencies. At room temperature, they demonstrated a lifetime T1≈23 ms and a retrieval efficiency η≈40% for classical coherent pulses. According to the researchers the storage of quantum light is possible at moderate cryogenic conditions (T≈10K) and such systems could find applications in emerging quantum networks, where they could serve as long-lived optical quantum memories by storing optical information in […]
Category Archives: Light
Could new technique for ‘curving’ light be the secret to improved wireless communication?
Science Daily April 9, 2024 A key challenge in millimeter-wave and terahertz wireless networks is blockage of the line-of-sight path between a base station and a user. A team of engineers in the US (University of Missouri-Kansas City, Rice University, Brown University) proposed a solution to this problem leveraging the fact that, in such scenarios, users are likely to be located within the electromagnetic near field of the base station, which opens the possibility to engineer wave fronts for link maintenance. They showed that curved beams, carrying data at high bit rates, could realize a link by curving around an […]
Propagating dimensions of light: Deforming versatile non-diffractive beams along the optical trajectory
Phys.org April 8, 2024 Despite the numerous types of non-diffraction beam generation technologies, the 3D deformation and intricate wavefront shaping of structures during propagation have yet to be studied through the lens of nanophotonic devices. An international team of researchers (Singapore, Spain) demonstrated the dynamic conversion of a circular Airy beam (CAB) to a Bessel beam with a single-layer spin-selective metasurface. The spatial transformation developed from the interplay of 1D local and 2D global phases, facilitating the 3D control of non-diffractive light fields. Overall phase gradient and orbital angular momentum altered the propagation direction and transverse fields of complex amplitude […]
Breakthrough in light manipulation: Unveiling novel finite barrier bound states
Phys.org March 22, 2024 A boundary mode localized on one side of a finite-size lattice can tunnel to the opposite side which results in unwanted couplings and the tunneling probability decays exponentially with the size of the system which requires many lattice sites before eventually becoming negligibly small. An international team of researchers (USA – PNNL, China) showed that the tunneling probability for some boundary modes can apparently vanish at specific wavevectors and a boundary mode can be completely trapped within very few lattice sites where the bulk bandgap is not even well-defined. The number of trapped states equaled the […]
Moebius rings enable new ways to control light in twisted spaces
Nanowerk March 21, 2024 Modulation of topological phase transition has been realized in Euclidean systems. However, the spin-controlled topological phase transition in non-Euclidean space has not yet been explored. Researchers in China proposed a non-Euclidean configuration based on Möbius rings, and demonstrated the spin-controlled transition between the topological edge state and the bulk state. They utilized 8π period Möbius rings to construct both one-dimensional and two-dimensional coupled resonator optical waveguide (CROW) configurations which supported topological edge states excited by circularly polarized light of a specific handedness, while forbidding the excitation of topological modes by light of the opposite handedness. This […]
Novel method for controlling light polarization uses liquid crystals to create holograms
Phys.org March 11, 2024 Metasurfaces are candidates for vectorial optics polarization, but their static post-fabrication geometry largely limits dynamic tunability. Liquid crystal (LC) is usually employed as an additional index-changing layer together with metasurfaces. However, most of the reported LCs only impart a varying but uniform phase on top of that from the metasurface. An international team of researchers (China, Singapore) pixelated a single-layer LC to display versatile and tunable vectorial holography, in which the polarization and amplitude could be arbitrarily and independently controlled at varying spatial positions. The subtle and vectorial LC-holography highlighted the broadband and electrically switchable functionalities. […]
Light stimulates a new twist for synthetic chemistry
Nanowerk February 28, 2024 Photoinduced concerted multiple-bond rotation has been proposed in some biological systems. However, the observation of such phenomena in synthetic systems has been a challenge in the photochemistry field. Researchers in Japan described a chalcogen-substituted benzamide system that exhibits photoinduced dual bond rotation in heteroatom-containing bonds. Introduction of the chalcogen substituent into a sterically hindered benzamide system provided sufficient kinetic stability and photosensitivity to enable the photoinduced concerted rotation. The presence of two different substituents on the phenyl ring in the thioamide derivative enabled the generation of a pair of enantiomers and E/Z isomers. Using these four […]
Measuring the properties of light: Scientists realize new method for determining quantum states
Nanowerk February 25, 2024 Superconducting nanowire single-photon detectors (SNSPDs) have been widely used to study the discrete nature of quantum states of light in the form of photon-counting experiments. Researchers in Germany showed that SNSPDs can also be used to study continuous variables of optical quantum states by performing homodyne detection at a bandwidth of 400 kHz. By measuring the interference of a continuous-wave field of a local oscillator with the field of the vacuum state using two SNSPDs, they showed that the variance of the difference in count rates was linearly proportional to the photon flux of the local […]
Illuminating the nanoscale: the forceful dance of light and heat
Nanowerk December 13, 2023 Despite its prevalence, the photothermal effect in light-absorbing nanoparticles has typically been assessed using bulk measurements, neglecting near-field effects. Beyond standard imaging and therapeutic uses, nanosecond-transient photothermal effects have been harnessed for bacterial inactivation, neural stimulation, drug delivery, and chemical synthesis. While scanning probe microscopy and electron microscopy offer single-particle imaging of photothermal fields, their slow speed limits observations to milliseconds or seconds, preventing nanoscale dynamic investigations. Researchers at the University of Illinois Urbana-Champaign introduced decoupled optical force nanoscopy (Dofn), enabling nanometer-scale mapping of photothermal forces by exploiting unique phase responses to temporal modulation. They employed […]
Bartering light for light: Scientists discover new system to control the chaotic behavior of light
Phys.org November 2, 2023 Prominent non-Hermitian phenomena include coherent perfect absorption and its generalization, reflectionless scattering modes, in which electromagnetic scattering at the input ports is suppressed due to critical coupling with the power leaked to output ports, and interference phenomena. These concepts are ideally suited to enable real-time dynamic control over absorption, scattering and radiation. However, reflectionless scattering modes have not been observed in complex photonic platforms involving open systems and multiple inputs. An international team of researchers (USA – City University of New York, Germany) demonstrated the emergence of reflectionless scattering modes in a chaotic photonic microcavity involving […]