Swift electrons can undergo inelastic interactions not only with electrons but also with near-fields, which may result in an energy loss or gain. Developments in photon-induced near-field electron microscopy (PINEM) enable direct imaging of the plasmon near-field distribution with nanometer resolution. Here, we report an analysis of the surface plasmonic near-field structure based on PINEM observations of silver nanowires. Single-photon order-selected electron images revealed the wavelike and banded structure of electric equipotential regions for a confined near-field integral associated with typical absorption of photon quanta (). Multimodal plasmon oscillations and second-harmonic generation were simultaneously observed, and the polarization dependence of plasmon wavelength and symmetry properties were analyzed. Based on advanced imaging techniques, our work has implications for future studies of the localized-field structures at interfaces and visualization of novel phenomena in nanostructures, nanosensors, and plasmonic devices.
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http://dx.doi.org/10.1021/acs.nanolett.1c03203 | DOI Listing |
Nat Commun
January 2025
School of Engineering Sciences, KTH Royal Institute of Technology, Applied Physics, AlbaNova, SE-106 91, Stockholm, Sweden.
Surface plasmons offer a promising avenue in the pursuit of swift and localized manipulation of magnetism for advanced magnetic storage and information processing technology. However, observing and understanding spatiotemporal interactions between surface plasmons and spins remains challenging, hindering optimal optical control of magnetism. Here, we demonstrate the spatiotemporal observation of patterned ultrafast demagnetization dynamics in permalloy mediated by propagating surface plasmon polaritons with sub-picosecond time- and sub-μm spatial- scales by employing Lorentz ultrafast electron microscopy combined with excitation through transient optical gratings.
View Article and Find Full Text PDFPlasmonic structured illumination microscopy (PSIM) is a super-resolution technique that utilizes surface plasmon polaritons (SPPs) with higher frequency as the structured light; thus, it is able to break the diffraction limit with a 3-4 times resolution enhancement. However, the low efficiency of near-field fluorescence collection results in a low imaging signal-to-noise ratio (SNR) of PSIM. In this paper, we propose a method to enhance the performance of PSIM with surface plasmon coupled emission (SPCE).
View Article and Find Full Text PDFThe extreme electromagnetic near-field environment of nanoplasmonic resonators and metamaterials can give rise to unprecedented electromagnetic heating effects, enabling large and manipulable temperature gradients on the order of 10-10 K/nm. In this Letter, by interfacing traditional semiconductor quantum dots with industry-grade plasmonic transducer technology, we demonstrate that the near-field-induced thermal gradient can facilitate the requisite population inversion for coherent phonon amplification and lasing at the nanoscale. Our detailed analysis uncovers both the characteristics and parameter sensitivity of inversion and relaxation oscillations in the system, thereby unveiling hitherto unexplored opportunities for leveraging plasmonic near-field effects in the context of quantum thermodynamics and phononics.
View Article and Find Full Text PDFNano Lett
January 2025
State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, 500 Yu Tian Road, Shanghai 200083, China.
Enhancing photoluminescence (PL) efficiency in colloidal quantum dots is pivotal for next-generation near-infrared photodetectors, imaging systems, and photonic devices. Conventional methods, especially metal-based plasmonic structures, suffer from large optical losses, which limits their practical use. Here, we introduce a quasi-bound state in the continuum (quasi-BIC) metasurface on a silicon-on-insulator platform, tailored to provide high-quality factor resonances with minimized losses.
View Article and Find Full Text PDFNat Commun
January 2025
Department of Nuclear, Plasma, and Radiological Engineering, The Grainger College of Engineering, University of Illinois Urbana-Champaign, Champaign, IL, USA.
Doped semiconductors can exhibit metallic-like properties ranging from superconductivity to tunable localized surface plasmon resonances. Diamond is a wide-bandgap semiconductor that is rendered electronically active by incorporating a hole dopant, boron. While the effects of boron doping on the electronic band structure of diamond are well-studied, any link between charge carriers and plasmons has never been shown.
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