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[ASME ASME 2018 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems - San Francisco, California, USA (Monday 27 August 2018)] ASME 2018 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems - Effect of Interfacial Thermal Conductance Between the Nanoparticles
摘要： Heat transport across nanostructured interfaces, such as between nanoparticles, has been of great interest for advanced thermal management. Interfacial thermal conductance, G, is central to understanding heat transport between nanoparticles that have a contact point between each other as well as the surrounded medium. In this study, we show that G dominates the heat transport compared to the conduction and radiation heat transfer modes between the nanoparticles for values higher than ~20 (MW/m2K). We also investigate the effect of radius of contact between the nanoparticles on the overall modes of heat transfer.
关键词： Nanoparticle Packings,Interfacial Thermal Conductance,Micro-Nanoscale Thermal Energy Transport
更新于2025-09-19 17:15:36
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Anisotropic nanoscale and sub-nanoscale friction behaviors between phosphorene and silicon tip
摘要： Understanding the frictional properties of phosphorene is essential for reliable fabrication and sustainable operation of phosphorene-based nanotechnology devices. Although recent studies have revealed that phosphorene exhibits anisotropic frictional characteristics, the detailed mechanisms are not well analyzed, and the influence of some experimental parameters (e.g., spring stiffness, tip load force, and tip size), which are very sensitive to atomic frictional forces, were not considered. This study was carried out to address the above shortcomings. The anisotropic frictional behavior of phosphorene and its detailed mechanism were analyzed using potential energy profiles. Also, the effects of spring stiffness and tip load force on the stick-slip behaviors were investigated. Furthermore, we studied the sub-nanoscale stick-slip behavior during the nanoscale slip motion. The nanoscale and sub-nanoscale stick-slip phenomena were originated from the tip’s behavior of passing over the bond between the phosphorus atoms and over the puckered honeycomb structure along the zigzag and armchair directions. We utilized a simple one-dimensional model to explain the energy profiles. The influence of tip size on the stick-slip behavior was also examined and found related to the initial nanoscale slip velocity. As the tip diameter decreased, a high-frequency sub-nanoscale stick-slip phenomenon and shorter nanoscale slip duration were identified.
关键词： nano/sub-nanoscale friction,phosphorene,stick-slip,molecular dynamics,friction force microscope
更新于2025-09-19 17:15:36
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Nanoscale lighta??matter interactions in metala??organic frameworks cladding optical fibers
摘要： The utilization of refractive index (RI) change due to guest–host interactions between the guest volatile organic compound vapor and porous metal–organic frameworks (vapor–MOF interactions) is promising in photonic vapor sensors. Therefore, the study of light–matter interactions in nanoporous metal–organic frameworks (MOFs) is fundamental and essential for MOF-based photonic devices. In this work, the manipulation of light in MOFs to investigate the vapor–MOF interactions by using optical fiber devices is demonstrated. The vapor–MOF interactions and the light–vapor interactions (light in MOFs to sense the RI changes resulting from the vapor–MOF interactions) are investigated. The cladding mode is excited by a long-period fiber grating (LPFG) for evanescent field sensing in a ZIF-8 sensitive coating. The experimental results combining quantum chemical calculations and optical simulations reveal the relationships between the microscopic energy of vapor desorption, RI changes and evanescent field enhancement in ZIF-8 during the vapor–MOF interactions. With exceptionally large RI changes, the evanescent field of cladding mode in ZIF-8 is greatly enhanced to sense the vapor–MOF interactions. As a proof-of-concept, a LPFG sensor with ZIF-8 coating showed a high sensitivity of 1.33 pm ppm?1 in the linear range from 9.8 ppm to 540 ppm for the sensing of ethanol vapor. The investigation of light–matter interactions in ZIF-8 provides a useful guideline for the design and fabrication of MOF-based optical waveguide/fiber sensors.
关键词： Nanoscale,metal–organic frameworks,light–matter interactions,vapor sensing,optical fibers
更新于2025-09-19 17:13:59
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Study of the physicochemical surface alterations and incubation phenomena induced on iron targets by nanosecond pulsed laser ablation in liquids: Effect on productivity and characteristics of the synthesized nanoscale zero-valent iron (nZVI) particles
摘要： This work presents a systematic study of the significant role of the surface physicochemical alterations produced during the laser ablation of massive iron disks submerged in different solvents on the generation of colloidal iron nanoparticles. For that purpose, the laser ablation thresholds and the incubation coefficients for various pulse numbers per site and pulse energies have been measured under distilled water (DW) and ethanol (EtOH). After that, a complete physicochemical characterization of these targets indicated higher threshold fluence values for the ablation experiments conducted in EtOH than those performed in DW. The threshold fluence values decreased also with the decrease of the pulse overlap for both solvents, being it much more pronounced in EtOH. In addition, the related incubation coefficient showed that the incubation effect is lower for experiments conducted in DW. The characteristics of the synthesized nZVI particles were also a function of the solvent nature and the pulse overlap: laser ablation in DW leaded to iron oxide nanoparticles, whereas core-shell iron nanoparticles were obtained in EtOH. Moreover, high pulse overlap values lead to chemical alterations, resulting in a decrease of the composition homogeneity and a strong increase of the nanoparticle polydispersity.
关键词： Incubation effect,Nanosecond pulsed laser ablation in liquids,Raman spectroscopy,Colloidal nanoscale zero-valent iron particles,Laser ablation threshold,Laser induced-chemical surface alteration
更新于2025-09-19 17:13:59
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Tunneling-induced broadband and tunable optical emission from plasmonic nanorod metamaterials
摘要： We demonstrate a metamaterial platform for electrically driven broadband light emission induced by electron tunneling. Both the Fabry-Perot and waveguided modes of the metamaterial slab as well the plasmonic mode of the tunneling gap are identified as contributing to shaping the emission spectrum. This opens up an opportunity to design the spectrum and polarization of the emitted light by tuning the metamaterial modes via the geometric parameters of the nanostructure throughout the visible and near-infrared spectral ranges. The efficient coupling of the tunneling-induced emission to the waveguided modes is beneficial for the development of integrated incoherent light sources, while the outcoupled emission provides a source of free-space radiation. The demonstrated incoherent nanoscale light sources may find applications in the development of integrated optoelectronic circuits, optical sensing platforms, imaging, and metrology.
关键词： plasmonics,nanoscale light sources,metamaterials,electron tunneling
更新于2025-09-19 17:13:59
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Ultra high-sensitivity and tunable dual-band perfect absorber as a plasmonic sensor
摘要： In this paper, we demonstrate a dual-band tunable absorber coupled with a nanoscale metal-dielectric-metal (MDM) structure for sensing applications in the near-infrared spectral region. This structure exhibits a dipole resonance mode in absorbance and reflectance spectra which results in the enhancement of absorbance over a wide range of incident angles for TE polarization. Using a numerical and analytical study, the performance parameters of the structure including sensitivity (SS), the figure of merit (FoM) and quality factor (Q) are investigated by changing the incident polarization, geometrical parameters, filling dielectric and plasmonic metasurface material. Moreover, we study the dependence of the sensitivity as a function of plasmonic metasurface shape to demonstrate a better response compared with other methods. Results show that, in terms of the refractive index unit (RIU), an ultra-high sensitivity and tunable sensor can be designed with a maximum sensitivity of 1240.8 nm/RIU for a refractive index change of Δn = 0.0458. In the optimum design of the proposed dual-band absorber, a Q-factor and FoM equal to 123.45 and 44.5 are obtained. Furthermore, the proposed structure can be utilized for controlling the light propagation. By considering silver as a plasmonic metasurface, a slow down factor as high as 680 is obtained. Our work will be applied to future sensors capable of ultra-high sensitivity.
关键词： Absorber,Nanoscale Structure,Plasmonics Sensor,Slow down factor,Metasurface
更新于2025-09-19 17:13:59
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[IEEE 2019 Days on Diffraction (DD) - St. Petersburg, Russia (2019.6.3-2019.6.7)] 2019 Days on Diffraction (DD) - Normal mode coupling in a waveguide with a range-dependent sound speed profile in the bottom
摘要： In this paper, a novel graphene-based multiple-input multiple-output (MIMO) concept is proposed for high-rate nanoscale wireless communications between transceivers, which are nano/micrometers apart from each other. In particular, the proposed MIMO architecture considers exploiting a deep-subwavelength propagation channel made of graphene. This allows us to increase the number of transmitted symbol streams, while using a deep-subwavelength arrangement of individual plasmonic nanotransmit/receive elements in which the spacing between the transmitters and/or the receivers is tens of times smaller than the wavelength. This exclusive benefit is achieved with the aid of the phenomenon of graphene plasmons, where graphene offers the extremely confined and low-loss plasmon propagation. Hence, the proposed graphene-based MIMO system is capable of combating the fundamental limitations imposed on the classic MIMO configuration. We also present a novel graphene-specific channel adaptation technique, where the chemical potential of the graphene channel is varied to improve the power of the received signals.
关键词： MIMO,surface plasmon polariton,nanoscale communication,chemical potential,graphene,Correlation,diffraction limit,deep subwavelength
更新于2025-09-19 17:13:59
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Two-stage optimal scheduling of air conditioning resources with high photovoltaic penetrations
摘要： Infrared chemical microscopy through mechanical probing of light?matter interactions by atomic force microscopy (AFM) bypasses the diffraction limit. One increasingly popular technique is photoinduced force microscopy (PiFM), which utilizes the mechanical heterodyne signal detection between cantilever mechanical resonant oscillations and the photoinduced force from the light?matter interaction. So far, PiFM has been operated in only one heterodyne configuration. In this Article, we generalize heterodyne configurations of PiFM by introducing two new schemes: harmonic heterodyne detection and sequential heterodyne detection. In harmonic heterodyne detection, the laser repetition rate matches integer fractions of the difference between the two mechanical resonant modes of the AFM cantilever. The high harmonic of the beating from the photothermal expansion mixes with the AFM cantilever oscillation to provide the PiFM signal. In sequential heterodyne detection, the combination of the repetition rate of laser pulses and the polarization modulation frequency matches the difference between two AFM mechanical modes, leading to detectable PiFM signals. These two generalized heterodyne configurations for PiFM deliver new avenues for chemical imaging and broadband spectroscopy at ～10 nm spatial resolution. They are suitable for a wide range of heterogeneous materials across various disciplines: from structured polymer film, to polaritonic boron nitride materials, to isolated bacterial peptidoglycan cell walls. The generalized heterodyne configurations introduce flexibility for the implementation of PiFM and the related tapping-mode AFM-IR and provide possibilities for an additional modulation channel in PiFM for targeted signal extraction with nanoscale spatial resolution.
关键词： photoinduced force microscopy,nanoscale spatial resolution,chemical imaging,Infrared chemical microscopy,heterodyne configurations,broadband spectroscopy
更新于2025-09-19 17:13:59
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Multipolar terahertz absorption spectroscopy ignited by graphene plasmons
摘要： Terahertz absorption spectroscopy plays a key role in physical, chemical and biological systems as a powerful tool to identify molecular species through their rotational spectrum fingerprint. Owing to the sub-nanometer scale of molecules, radiation-matter coupling is typically dominated by dipolar interaction. Here we show that multipolar rotational spectroscopy of molecules in proximity of localized graphene structures can be accessed through the extraordinary enhancement of their multipolar transitions provided by terahertz plasmons. In particular, specializing our calculations to homonuclear diatomic molecules, we demonstrate that a micron-sized graphene ring with a nano-hole at the core combines a strong near-field enhancement and an inherently pronounced field localization enabling the enhancement of the dipole-forbidden terahertz absorption cross-section of H+2 by 8 orders of magnitude. Our results shed light on the strong potential offered by nano-structured graphene as a robust and electrically tunable platform for multipolar terahertz absorption spectroscopy at the nanoscale.
关键词： graphene plasmons,multipolar transitions,nanoscale,Terahertz absorption spectroscopy
更新于2025-09-19 17:13:59
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[IEEE 2019 Photonics & Electromagnetics Research Symposium - Fall (PIERS - Fall) - Xiamen, China (2019.12.17-2019.12.20)] 2019 Photonics & Electromagnetics Research Symposium - Fall (PIERS - Fall) - Parametric Simulation of a??Hot-wirea??-based Gas Velocity Sensor Using Optical Fiber
摘要： A new quadrature oscillator topology is proposed, which arranges four low-Q series LC tanks in a ring structure driven by inverters operating in class-D. With a very small area of 0.007 that is comparable to conventional ring oscillators, this oscillator has 7–20 dB better phase noise FoM of 177 dB. It is widely tunable for nearly an octave from 2.66 to 4.97 GHz.
关键词： low inductor,phase noise,wide tuning,low area,quadrature oscillator,LC oscillator,ring oscillator,series LC,Class-D oscillator,nanoscale CMOS
更新于2025-09-19 17:13:59