We report on a dramatic directionality effect in a simple and ultracompact optical nanoantenna consisting of a pair of interacting plasmonic nanoparticles. We found that the emission from a dipole source positioned close to one of the particles in the pair exhibits an essentially unidirectional radiation pattern for emission wavelengths close to the antiphase hybridized plasmon. We analyze this unique effect in terms of radiation, reception, and reciprocity concepts using electrodynamics simulations and dipole analysis. A forward-backward directionality of approximately 18 dB at 665 nm is obtained for a nanoantenna that consists of two 90 nm wide and 20 nm thick gold nanodisks separated by a 10 nm gap.
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http://dx.doi.org/10.1021/nl900786u | DOI Listing |
ACS Nano
January 2025
Institute of Photonics and of Nanotechnologies- National Researcher Council (IFN-CNR), LNESS Laboratory, Piazza Leonardo Da Vinci 32, 20133 Milano, Italy.
Manipulating the optical landscape of single quantum dots (QDs) is essential to increase the emitted photon output, enhancing their performance as chemical sensors and single-photon sources. Micro-optical structures are typically used for this task, with the drawback of a large size compared to the embedded single emitters. Nanophotonic architectures hold the promise to modify dramatically the emission properties of QDs, boosting light-matter interactions at the nanoscale, in ultracompact devices.
View Article and Find Full Text PDFLight Sci Appl
January 2025
Department of Physics, Chalmers University of Technology, 412 96, Gothenburg, Sweden.
Nanostructured dielectric metasurfaces offer unprecedented opportunities to control light-matter momentum exchange, and thereby the forces and torques that light can exert on matter. Here we introduce optical metasurfaces as components of ultracompact untethered microscopic metaspinners capable of efficient light-induced rotation in a liquid environment. Illuminated by weakly focused light, a metaspinner generates torque via photon recoil through the metasurfaces' ability to bend light towards high angles despite their sub-wavelength thickness, thereby creating orbital angular momentum.
View Article and Find Full Text PDFNanophotonics
November 2024
Key Laboratory of Ultra-Weak Magnetic Field Measurement Technology, Ministry of Education, School of Instrumentation and Optoelectronic Engineering, Beihang University, Beijing 100191, China.
Atomic magnetometers (AMs) that use alkali vapors, such as rubidium, are among the most sensitive sensors for magnetic field measurement. They commonly use polarization differential detection to mitigate common-mode noise. Nevertheless, traditional differential detection optics, including polarization beam splitters (PBS) and half-wave plates, are typically bulky and large, which restricts further reductions in sensor dimensions.
View Article and Find Full Text PDFMed Phys
December 2024
Faculty of Engineering, Hokkaido University, Sapporo, Japan.
Background: Protoacoustics has emerged as a promising real-time range measurement method for proton therapy. Optical hydrophones (OHs) are considered suitable to detect protoacoustic waves owing to their ultracompact size and high sensitivity. In our previous research, we demonstrated that the time-of-arrival (TOA) measured by an OH showed good agreement with the simulated ground truth in a homogeneous medium.
View Article and Find Full Text PDFNanophotonics
September 2024
Electronic Information School, and School of Microelectronics, Wuhan University, Wuhan 430072, China.
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