Phys.org April 24, 2024 Although in electronic crystals, magnetic fields can be used to induce a multitude of unique phenomena, the uncharged nature of photons necessitates alternative approaches to bring about similar control over photons at the nanoscale. Researchers in the Netherlands demonstrated experimentally pseudomagnetic fields in two-dimensional photonic crystals through engineered strain of the lattice. Taking advantage of the photonic crystal’s design freedom, they realized domains of opposite pseudomagnetic field and observed chiral edge states at their interface. They revealed that the strain-induced states could achieve remarkably high quality factors despite being phase matched to the radiation continuum. Together […]
Tag Archives: Light-matter interaction
A single photon emitter deterministically coupled to a topological corner state
Phys.org April 2, 2024 Researchers in China presented a single photon emitter that utilizes a single semiconductor quantum dot, deterministically coupled to a second-order topological corner state in a photonic crystal cavity. By investigating the Purcell enhancement of both single photon count and emission rate within this topological cavity, they got an experimental Purcell factor of Fp = 3.7. They demonstrated the on-demand emission of polarized single photons, with a second-order autocorrelation function g(2)(0) as low as 0.024 ± 0.103. According to the researchers their work may be used for customizing light-matter interactions in topologically nontrivial environments… read more. Open Access TECHNICAL ARTICLE
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 […]
Breaking boundaries in quantum photonics: New nanocavities unlock new frontiers in light confinement
Phys.org February 5, 2024 Confinement of light into nanocavities which enhances light–matter interactions generally come at the cost of absorption and low resonator quality factors. An international team of researchers (Israel, USA – Cornell University, Kansas State University, Germany, Spain) suggested an alternative optical multimodal confinement mechanism, unlocking the potential of hyperbolic phonon polaritons in isotopically pure hexagonal boron nitride. They produced deep-subwavelength cavities and demonstrated several orders of magnitude improvement in confinement approaching the intrinsic quality factor of hexagonal boron nitride polaritons. The quality factors they obtained exceeded the maximum predicted by impedance-mismatch considerations indicating that confinement was boosted […]
Communing with nothingness
Nanowerk November 6, 2023 Light–matter interaction in the ultrastrong coupling regime is attracting considerable attention owing to its applications to coherent control of material properties by a vacuum fluctuation field. However, electrical access to such an ultra-strongly coupled system is very challenging. Researchers in Japan have fabricated a gate-defined quantum point contact (QPC) near the gap of a terahertz (THz) split-ring resonator (SRR) fabricated on a GaAs two-dimensional (2D) electron system. By illuminating the system with external THz radiation, the QPC showed a photocurrent spectrum which exhibited significant anticrossing that came from coupling between the cyclotron resonance of the 2D […]
Shrinking light: Waveguiding scheme enables highly confined subnanometer optical fields
Phys.org July 17, 2023 Researchers in China developed an optical waveguide scheme to generate a sub-nanometer-confined optical field in a nano slit waveguiding mode in a coupled nanowire pair (CNP). They showed that, when a conventional waveguide mode with a proper polarization was evanescently coupled into a properly designed CNP with a central nano slit, it could be channeled into a high-purity nano slit mode within a waveguiding length <10 μm. The CNP could be either freestanding or on-chip by using a tapered fiber or planar waveguide for input-coupling, with a coupling efficiency up to 95%. Within the slit region, […]
When the light is neither ‘on’ nor ‘off’ in the nanoworld
Phys.org February 14, 2023 Plasmon modes are treated as quasiparticles, and they are considered essential for the realization of future nanoscale quantum functionality. Implementing and demonstrating such functionality requires access to the quasiparticle’s quantum state to monitor and manipulate its corresponding quantum wave packet dynamics in Hilbert space. Researchers in Germany succeeded in detecting such superposition states of light directly in a nanostructure using plasmon-assisted electron emission as a signal in coherent two-dimensional nanoscopy. The observation of a quantum coherence oscillating at the third harmonic of the plasmon frequency was traced back to the superposition of energetically non-adjacent plasmon occupation […]
Researchers use ultrasound waves to move objects hands-free
Science Daily December 6, 2022 The transfer of wave momentum is a fundamental mechanism for contactless manipulation, yet the rules of conventional scattering intrinsically limit the radiation force based on the shape and the size of the manipulated object. Researchers at the University of Minnesota showed that this intrinsic limit can be broken for acoustic waves with subwavelength metasurfaces. Harnessing anomalous metasurface scattering, they demonstrated self-guidance, where a metasurface object is autonomously guided by an acoustic wave, and tractor beaming, where a metasurface object is pulled by the wave. According to the researchers their results show that bringing the metasurface […]
Researchers suggest novel way to generate a light source made from entangled photons
Phys.org September 9, 2022 Researchers at Purdue University have proposed the generation of attosecond entangled biphotons in the extreme-ultraviolet regime by two-photon decay of a metastable atomic state as a source like spontaneous parametric down-conversion photons. The 1s2s1S0 metastable state in helium decays to the ground state by the emission of two energy-time entangled photons with a photon bandwidth equal to the total energy spacing of 20.62 eV. This results in a pair correlation time in the attosecond regime making these entangled photons a highly suitable source for attosecond pump-probe experiments. They calculated and used the biphoton generation rate from […]
Nanoclusters self-organize into centimeter-scale hierarchical assemblies
Phys.org April 22, 2022 An international team of researchers (USA – Cornell University, Rochester Institute of Technology, Canada) has created synthetic nanoclusters from an organic–inorganic mesophase composed of monodisperse Cd37S18 magic-size cluster building blocks. The process produced “magic-size clusters” of 57 atoms, about 1.5 nanometers in length. Each of these nanoparticles had a shell of ligands that could interact with each other in such a way that they formed filaments several microns long and hundreds of nanometers wide. The filaments were periodically decorated with the magic-size clusters with perfect spacing between them. Enhanced patterning was achieved by controlling processing conditions, […]