scholarly journals Exploring the scattering directionality and light interaction in nanoparticle dimers of different semiconductors

2017 ◽  
Vol 9 (2) ◽  
pp. 42
Author(s):  
Ricardo Vergaz Benito ◽  
Braulio García-Cámara ◽  
José Francisco Algorri ◽  
Alexander Cuadrado ◽  
José Manuel Sánchez-Pena
Keyword(s):  
Electric Fields ◽  
Silicon Nanoparticles ◽  
Scattered Light ◽  
High Refractive Index ◽  
Semiconductor Nanoparticles ◽  
Optical Antennas ◽  
Ieee Photon ◽  
Starting Point ◽  
All Optical ◽  
Light Interaction

Assuming as a starting point our recent work on a dimer of silicon nanoparticles with light scattering directionality, we have explored the light interaction between the incoming and scattered electric fields in dimers made of other different semiconductors. The scattering directionality is achieved by accomplishing Kerker's conditions. By directing the scattered light towards the gap of the dimer, interferential effects can be used to achieve high or low light intensities as a basis of all-optical nanoswitches. A comparison between dimers of different materials is shown. Full Text: PDF ReferencesR. Gómez-Medina, B. García-Cámara, I. Súarez-Lacalle, F. González, F. Moreno, M. Nieto-Vesperias and J.J. Sáenz, "Electric and magnetic dipolar response of germanium nanospheres: interference effects, scattering anisotropy, and optical forces", J. Nanophoton. 5 053512 (2011). CrossRef B. Rolly, B. Stout and N. Bonod, "Boosting the directivity of optical antennas with magnetic and electric dipolar resonant particles", Opt. Express 20 20376 (2012). CrossRef B. García-Cámara, R. Gómez-Medina, J.J. Sáenz, and B. Sepúlveda, "Sensing with magnetic dipolar resonances in semiconductor nanospheres", Opt. Express 21 23007-23020 (2013). CrossRef B. García-Cámara et al., "All-Optical Nanometric Switch Based on the Directional Scattering of Semiconductor Nanoparticles", J. Phys. Chem. C. 119, 19558?19564 (2015). CrossRef A.I. Barreda, H. Saleh, A. Litman, F. González, J-M. Geffrin, and F. Moreno, "Electromagnetic polarization-controlled perfect switching effect with high-refractive-index dimers and the beam-splitter configuration", Nat. Commun. 8, 13910 (2017). CrossRef R. Vergaz et al., "Control of the Light Interaction in a Semiconductor Nanoparticle Dimer Through Scattering Directionality", IEE Phot. Jour., 8(3), 4501410 (2016) CrossRef B. García-Cámara et al., "Size Dependence of the Directional Scattering Conditions on Semiconductor Nanoparticles", IEEE Photon. Technol. Lett. 27(19), 2059?2062 (2015). CrossRef

scholarly journals Endogenous and exogenous electric fields as modifiers of brain activity: rational design of noninvasive brain stimulation with transcranial alternating current stimulation

2014 ◽  
Vol 16 (1) ◽  
pp. 93-102 ◽  
Keyword(s):  
Electric Fields ◽  
Brain Stimulation ◽  
Rational Design ◽  
Brain Activity ◽  
Field Potential ◽  
Alternating Current ◽  
Noninvasive Brain Stimulation ◽  
Starting Point ◽  
Recent Developments ◽  
Transcranial Alternating Current Stimulation

Synchronized neuronal activity in the cortex generates weak electric fields that are routinely measured in humans and animal models by electroencephalography and local field potential recordings. Traditionally, these endogenous electric fields have been considered to be an epiphenomenon of brain activity. Recent work has demonstrated that active cortical networks are surprisingly susceptible to weak perturbations of the membrane voltage of a large number of neurons by electric fields. Simultaneously, noninvasive brain stimulation with weak, exogenous electric fields (transcranial current stimulation, TCS) has undergone a renaissance due to the broad scope of its possible applications in modulating brain activity for cognitive enhancement and treatment of brain disorders. This review aims to interface the recent developments in the study of both endogenous and exogenous electric fields, with a particular focus on rhythmic stimulation for the modulation of cortical oscillations. The main goal is to provide a starting point for the use of rational design for the development of novel mechanism-based TCS therapeutics based on transcranial alternating current stimulation, for the treatment of psychiatric illnesses.

scholarly journals All-optical comparator based on linear chain of silicon nanoparticles

2020 ◽  
Vol 1482 ◽  
pp. 012033
Author(s):  
A A Sapegin ◽  
M Yu Barabanenkov ◽  
A G Italyantsev
Keyword(s):  
Silicon Nanoparticles ◽  
Linear Chain ◽  
All Optical

scholarly journals Ultrafast all-optical switching with photonic nanojets and semiconductor nanoparticles

2016 ◽  
Author(s):  
Brandon Born ◽  
Jeffrey D. A. Krupa ◽  
Simon Geoffroy-Gagnon ◽  
Jonathan F. Holzman
Keyword(s):  
Optical Switching ◽  
Semiconductor Nanoparticles ◽  
All Optical ◽  
Photonic Nanojets ◽  
All Optical Switching

scholarly journals All-Optical Nanometric Switch Based on the Directional Scattering of Semiconductor Nanoparticles

2015 ◽  
Vol 119 (33) ◽  
pp. 19558-19564 ◽  
Author(s):  
Braulio García-Cámara ◽  
J. Francisco Algorri ◽  
Alexander Cuadrado ◽  
Virginia Urruchi ◽  
José Manuel Sánchez-Pena ◽  
...  
Keyword(s):  
Semiconductor Nanoparticles ◽  
All Optical

scholarly journals Measurement of the Near Field Distribution of a Microwave Horn Using a Resonant Atomic Probe

2019 ◽  
Vol 9 (22) ◽  
pp. 4895 ◽  
Author(s):  
Jingxu Bai ◽  
Jiabei Fan ◽  
Liping Hao ◽  
Nicholas L. R. Spong ◽  
Yuechun Jiao ◽  
...  
Keyword(s):  
Field Distribution ◽  
Electric Fields ◽  
Microwave Field ◽  
Electric Field Distribution ◽  
Near Field ◽  
Field Measurements ◽  
Amplitude Distribution ◽  
Field Coupling ◽  
All Optical ◽  
Atomic Probe

We measure the near field distribution of a microwave horn with a resonant atomic probe. The microwave field emitted by a standard microwave horn is investigated utilizing Rydberg electromagnetically inducted transparency (EIT), an all-optical Rydberg detection, in a room temperature caesium vapor cell. The ground 6 S 1 / 2 , excited 6 P 3 / 2 , and Rydberg 56 D 5 / 2 states constitute a three-level system, used as an atomic probe to detect microwave electric fields by analyzing microwave dressed Autler–Townes (AT) splitting. We present a measurement of the electric field distribution of the microwave horn operating at 3.99 GHz in the near field, coupling the transition 56 D 5 / 2 → 57 P 3 / 2 . The microwave dressed AT spectrum reveals information on both the strength and polarization of the field emitted from the microwave horn simultaneously. The measurements are compared with field measurements obtained using a dipole metal probe, and with simulations of the electromagnetic simulated software (EMSS). The atomic probe measurement is in better agreement with the simulations than the metal probe. The deviation from the simulation of measurements taken with the atomic probe is smaller than the metal probe, improving by 1.6 dB. The symmetry of the amplitude distribution of the measured field is studied by comparing the measurements taken on either side of the field maxima.

Physical Chemistry of Hydrogenous Species in the Si-Si02 System

1995 ◽  
Vol 50 (7) ◽  
pp. 653-665 ◽  
Author(s):  
Edward H. Poindexter
Keyword(s):  
Physical Chemistry ◽  
Electric Fields ◽  
Bias Field ◽  
Fused Silica ◽  
Crystalline Quartz ◽  
Device Processing ◽  
Starting Point ◽  
Electrified Interface ◽  
High Electric Fields ◽  
Electrochemical Model

Research on hydrogenous species in the Si-Si02 system is reviewed and examined. Some aspects of thermal silica on silicon are explained by comparison with crystalline quartz or bulk amorphous fused silica. Hydrogen behavior in the Si-Si02 system is complicated by the unique features of device processing technology, an electrified interface, and high electric fields. An electrochemical model of the negative-bias-field-induced degradation of the system is used as a starting point for discussion of diffusion and solubility, atomic H disposition, thermochemical phenomena, and radiation damage. It is thereby hoped to provide new approaches for complete modeling of hydrogen physical chemistry in the Si-Si02 system.

scholarly journals Electrometry by optical charge conversion of deep defects in 4H-SiC

2018 ◽  
Vol 115 (31) ◽  
pp. 7879-7883 ◽  
Author(s):  
G. Wolfowicz ◽  
S. J. Whiteley ◽  
D. D. Awschalom
Keyword(s):  
Electric Fields ◽  
High Frequency ◽  
Room Temperature ◽  
Field Energy ◽  
Active Point ◽  
Rate Dependent ◽  
Host Materials ◽  
All Optical ◽  
Field Energy Density ◽  
Optical Charge

Optically active point defects in various host materials, such as diamond and silicon carbide (SiC), have shown significant promise as local sensors of magnetic fields, electric fields, strain, and temperature. Modern sensing techniques take advantage of the relaxation and coherence times of the spin state within these defects. Here we show that the defect charge state can also be used to sense the environment, in particular high-frequency (megahertz to gigahertz) electric fields, complementing established spin-based techniques. This is enabled by optical charge conversion of the defects between their photoluminescent and dark charge states, with conversion rate dependent on the electric field (energy density). The technique provides an all-optical high-frequency electrometer which is tested in 4H-SiC for both ensembles of divacancies and silicon vacancies, from cryogenic to room temperature, and with a measured sensitivity of 41±8(V/cm)2/Hz. Finally, due to the piezoelectric character of SiC, we obtain spatial 3D maps of surface acoustic wave modes in a mechanical resonator.

scholarly journals Individual Split Au Square Ring for Surface Enhanced Raman and Hyper-Raman Scattering

2021 ◽  
Author(s):  
RuXin ZHang ◽  
Chaoling Du ◽  
Lu Sun ◽  
Wang XuRong ◽  
Xiang Li ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Electric Fields ◽  
Near Infrared ◽  
Scattered Light ◽  
Localized Surface Plasmon ◽  
Great Promise ◽  
Sensitivity Factor ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Potential Applications

Abstract In this paper, individual split Au square rings were numerically proposed as novel substrates for surface enhanced Raman and hyper-Raman scattering (SERS and SEHRS) simultaneously. The peak wavelengths of their localized surface plasmon resonances (LSPR) are revealed to fall in the near-infrared and visible light region, respectively, which are able to be finely tuned to match well with the wavelengths of the incident laser and hyper Raman scattered light beams. Their SEHRS and SERS performances along with electromagnetic (EM) field distributions are numerically investigated by finite element method. With the enhancement of near electric-fields generated by LSPRs, the maximum SEHRS and SERS enhancement factors are demonstrated to reach 1.22×1012 and 108, respectively. Meanwhile, the corresponding SERS based refractive-index (RI) sensitivity factor reaches as high as 258nm/RIU and 893nm/RIU, at visible and near-infrared wavelengths, respectively. The proposed structure is believed to hold great promise both for developing SEHRS, SERS and SERS based RI sensing substrates, which shows strong potential applications in nano sensing and enhanced Raman scattering.

scholarly journals Efficient ultrafast all-optical modulation in a nonlinear crystalline gallium phosphide nanodisk at the anapole excitation

2020 ◽  
Vol 6 (34) ◽  
pp. eabb3123 ◽  
Author(s):  
Gustavo Grinblat ◽  
Haizhong Zhang ◽  
Michael P. Nielsen ◽  
Leonid Krivitsky ◽  
Rodrigo Berté ◽  
...  
Keyword(s):  
Gallium Phosphide ◽  
Optical Switching ◽  
Near Infrared ◽  
High Refractive Index ◽  
Photon Absorption ◽  
Optical Modulation ◽  
Infrared Range ◽  
Two Photon Absorption ◽  
All Optical ◽  
Differential Reflectivity

High–refractive index nanostructured dielectrics have the ability to locally enhance electromagnetic fields with low losses while presenting high third-order nonlinearities. In this work, we exploit these characteristics to achieve efficient ultrafast all-optical modulation in a crystalline gallium phosphide (GaP) nanoantenna through the optical Kerr effect (OKE) and two-photon absorption (TPA) in the visible/near-infrared range. We show that an individual GaP nanodisk can yield differential reflectivity modulations of up to ~40%, with characteristic modulation times between 14 and 66 fs, when probed at the anapole excitation (AE). Numerical simulations reveal that the AE represents a unique condition where both the OKE and TPA contribute with the same modulation sign, maximizing the response. These findings highly outperform previous reports on sub–100-fs all-optical switching from resonant nanoscale dielectrics, which have demonstrated modulation depths no larger than 0.5%, placing GaP nanoantennas as a promising choice for ultrafast all-optical modulation at the nanometer scale.

An Innovative Approach to CTCs’ Liquid Surgery

2020 ◽  
Author(s):  
Luca Fontanili ◽  
Massimo Milani ◽  
Luca Montorsi ◽  
Letizia Scurani ◽  
Matteo Venturelli ◽  
...  
Keyword(s):  
Blood Flow ◽  
Physical Properties ◽  
Tumor Cells ◽  
Medical Device ◽  
Electric Fields ◽  
Ad Hoc ◽  
Starting Point ◽  
Baseline Information ◽  
Flow Through ◽  
Complicated Geometries

Abstract Circulating Tumor Cells (CTCs) can be defined as cancerous cells, which detach from a tumor and flow through the vascular or lymphatic systems. The blood flow can carry the tumor cells in another region of human body where they can become the starting point for the growth of additional metastases. Because of this behavior, in the CTCs study it is paramount to acquire new data and knowledge to understand the mechanisms that lead to the separation of the cell from the tumor as well as the major characteristics of these cells. The aim of this work is the development of an innovative therapeutic and diagnostic approach able to lead to a new medical device for removing CTCs from the peripheral blood of a patient. The main target of the approach is to detect the CTCs and separate them during a conventional extracorporeal circulation procedure, similar to that used for renal failure. In this work, the CTCs physical properties are investigated in order to explore the possible characteristics that can be exploited in an ad-hoc developed medical device to remove them from the blood flow. The CTCs physical properties are analyzed numerically, and their behavior is studied by means of CFD simulations. The preliminary numerical tests have been carried out on simple geometries in order to assess the influence of magnetic and electric fields on tumor cells’ trajectory. These results are the baseline information to develop more complicated geometries and prototypes for real operations.

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