scholarly journals No light at the end of the tunnel

2021 ◽  
Vol 75 (5) ◽  
Author(s):  
H. R. Reiss
Keyword(s):  
Charged Particle ◽  
Electric Field ◽  
Electric Fields ◽  
Quantum Tunneling ◽  
Laser Field ◽  
Laser Light ◽  
Particle Interactions ◽  
Propagation Property ◽  
Tunneling Model ◽  
Low Frequencies

Abstract The tunneling model for laser-induced processes implies the replacement of the propagating field of a laser by an oscillatory electric field. The view of the electric field as the primary influence in charged particle interactions fails for laser processes where the propagation property is important. Electric fields lack several quintessential laser-field properties that become dominant at high intensities and/or low frequencies. Quantum tunneling is not a concept generally suited to laser light. Conversely, laser criteria do not apply to electric-field phenomena like Sauter–Schwinger pair production in the vacuum, contrary to a widespread assumption. Graphic abstract

scholarly journals High-efficiency acceleration by the combination of laser and electrostatic field

2014 ◽  
Vol 32 (4) ◽  
pp. 577-581 ◽  
Author(s):  
H. Lin ◽  
C.P. Liu ◽  
C. Wang ◽  
B.F. Shen
Keyword(s):  
Magnetic Field ◽  
Particle Acceleration ◽  
Charged Particle ◽  
Electric Field ◽  
Laser Field ◽  
High Efficiency ◽  
Single Body ◽  
Body Dynamics ◽  
High Kinetic Energy ◽  
Dc Electric Field

AbstractA new scheme of particle acceleration is verified by the investigation on single-body dynamics of charged particle in a compound field setup. This compound field setup contains a linear polarized laser field and a DC electric field which is along the direction of laser magnetic field. This setup can cause a charged particle to be of aperiodic motion and significantly high kinetic energy. Moreover, the contribution from the motion vertical to accelerating electric field is fully taken into account and is found to be essential to efficient acceleration. The efficiency of such a setup in acceleration is higher than that of a single laser.

Choice of Electrode Material for Detecting Low Frequency Electric Field in Sea Water

2011 ◽  
Vol 239-242 ◽  
pp. 137-140 ◽  
Author(s):  
Yu Su Song ◽  
Kun Zhang ◽  
Pan Zuo
Keyword(s):  
Solid State ◽  
Electric Field ◽  
Electric Fields ◽  
Electrode Material ◽  
Sea Water ◽  
Low Frequency ◽  
Low Frequencies ◽  
Voltage Difference ◽  
Frequency Electric Field ◽  
Sensitive Electrode

Seven types of electrodes have been selected. DC resistances, AC impedances and voltage difference of the electrode pairs have been studied, according to the requirement of low and extra low frequencies electric fields detection in sea water. The feasibilities of these electrodes used for detecting these signals have been studied and explained on theories. The results show that the all-solid-state Ag/AgCl electrode is the most sensitive electrode with its very low DC resistances, AC impedances and the voltage difference controlled within 20μV, which makes it detecting low frequency electric field accurately.

Dielectrophoresis of Nanoparticles

2004 ◽  
Author(s):  
Arun Thankamony John Kadaksham ◽  
Pushpendra Singh ◽  
Nadine Aubry
Keyword(s):  
Brownian Motion ◽  
Electric Field ◽  
Electric Fields ◽  
Numerical Scheme ◽  
Relative Magnitude ◽  
Hydrodynamic Forces ◽  
Uniform Electric Field ◽  
Particle Interactions ◽  
Particle Trajectories ◽  
Random Manner

A numerical scheme based on the distributed Lagrange multiplier method (DLM) is used to study the motion of nano sized particles of dielectric suspensions subjected to uniform and nonuniform electric fields. Particles are subjected to both electrostatic and hydrodynamic forces, as well as Brownian motion. The results of the simulations presented in this paper show that in the case of uniform electric fields the evolution of the particle structures depends on the ratio of electrostatic particle-particle interactions and Brownian forces. For solids fraction of the order 0.01, when this ratio is of the order of a hundred or more particles form stable chains and columns whereas when this ratio is of the order ten the particles are distributed in a random manner. For the non uniform electric field cases considered in this paper, the relative magnitude of Brownian forces is in the range such that it does not influence the eventual collection of particles by dielectrophoresis and the particular locations where the particles are collected. However, Brownian motion is observed to influence the transient particle trajectories. The deviation of the particle trajectories compared to those determined by the electrostatic and hydrodynamic forces alone is characterized by the ratio of Brownian and dielectrophoretic forces.

A New Technique for Determining Midgap States and Hole Localization in a-Si:H Devices

1990 ◽  
Vol 192 ◽  
Author(s):  
Vikarm L. Dalal ◽  
Ralph D. Knox
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Reverse Bias ◽  
Reverse Bias Voltage ◽  
Tunneling Model ◽  
Major Consequence ◽  
A New Technique ◽  
High Electric Fields ◽  
Gap States ◽  
Hole Localization

ABSTRACTWe describe a technique for measuring localization of holes in mid-gap states in high quality a-Si:H devices. The localization of holes is determined by measuring quantum efficiency of a-Si:H devices as a function of reverse bias voltage and wavelength of light. It is shown that the QE of localized holes increases significantly upon application of high electric fields, whereas the QE of de-localized holes does not show such a behavior. The voltage-induced increase in QE is explained using a Frenkel-Poole tunneling model. It is also shown that the density of mid-gap states (states in which holes are localized) increases significantly upon light soaking, and that a major consequence of this increase in mid-gap density is a decrease in the electric field in the device. The decrease in electric field is experimentally estimated by fitting the increased current due to tunneling to the expression for Frenkel-Poole tunneling.

Lightning, Evolution and Biology

2020 ◽  
Author(s):  
Colin Price ◽  
Earle Williams ◽  
Gal Elhalel ◽  
Dave Sentman
Keyword(s):  
Electric Field ◽  
Electrical Activity ◽  
Electric Fields ◽  
Evolutionary History ◽  
Natural Background ◽  
Resonant Frequencies ◽  
Low Frequencies ◽  
Present Evidence ◽  
History Of ◽  
Living Organisms

<p>Most electrical activity in vertebrates and invertebrates occurs at extremely low frequencies (ELF), with characteristic maxima below 50Hz.  The origin of these frequency maxima is unknown and remains a mystery.  We propose that over billions of years during the evolutionary history of living organisms on Earth, the natural electromagnetic resonant frequencies in the atmosphere, continuously generated by global lightning activity, provided the background electric fields for the development of cellular electrical activity.  In some animals the electrical spectrum is difficult to differentiate from the natural background atmospheric electric field produced by lightning.  In this paper we present evidence for the link between the natural ELF fields and those found in many living organisms, including humans.</p><p>Price, C., E. Williams, G., Elhalel and D. Sentman, 2020:  Natural ELF Fields in the Atmosphere and in Living Organisms, <em>Int. J. Biometeorology, </em>in press.</p>

scholarly journals Self-Organization of Charged Particles in an Electric Field

2021 ◽  
pp. 46-62
Author(s):  
William J. B. Oldham Jr.
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Charged Particles ◽  
Opposite Polarity ◽  
Self Organization ◽  
Constant Field ◽  
Particle Interactions ◽  
Small Systems ◽  
System States ◽  
Final System

Self-organization in small systems of particles with simple dynamic laws has been simulated. The purpose of this work was to investigate self-organization in small systems of charged particles under the influence of an electric field where we could follow individual particles. There are positively and negatively charged particles. The intention is to look for pattern formation as the system evolves. Three electric fields and the particle-to-particle interactions were utilized to provide the forces. The three electric fields were a constant field, a ramp field, and an oscillatory field. The final system states for various electric fields are presented. For the two kinds of particles simulated, like particles have a repulsive force, while unlike particles have an attractive force. Initially, the particles are randomly distributed in a two dimensional square bounded region, and then allowed to dynamically interact for a number of iterations. Using the inverse square law force, modified at short distances, most cases resulted in equilibrium with the particles of opposite polarity paired up. Since this was a state of equilibrium no more movement occurred. The results of the experiments are presented in graphical format. The main conclusions are that this model can be used to study small dynamic systems, and that the presence of an external electric field does not significantly modify the final configuration but hastens the development of the equilibrium state.

Relativistic charged-particle interactions in a chaotic laser field

1984 ◽  
Vol 30 (5) ◽  
pp. 2245-2255 ◽  
Author(s):  
W. Becker ◽  
M. O. Scully ◽  
K. Wódkiewicz ◽  
M. S. Zubairy
Keyword(s):  
Charged Particle ◽  
Laser Field ◽  
Particle Interactions ◽  
Chaotic Laser ◽  
Relativistic Charged Particle

Tuning the Electric Field Response of MOFs by Rotatable Dipolar Linkers

2019 ◽  
Author(s):  
Johannes P. Dürholt ◽  
Babak Farhadi Jahromi ◽  
Rochus Schmid
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Structural Changes ◽  
Dielectric Behavior ◽  
Two Dimensions ◽  
Dielectric Constants ◽  
Electric Response ◽  
Dipole Strength ◽  
Metal Organic ◽  
Dynamics Simulations

Recently the possibility of using electric fields as a further stimulus to trigger structural changes in metal-organic frameworks (MOFs) has been investigated. In general, rotatable groups or other types of mechanical motion can be driven by electric fields. In this study we demonstrate how the electric response of MOFs can be tuned by adding rotatable dipolar linkers, generating a material that exhibits paralectric behavior in two dimensions and dielectric behavior in one dimension. The suitability of four different methods to compute the relative permittivity κ by means of molecular dynamics simulations was validated. The dependency of the permittivity on temperature T and dipole strength μ was determined. It was found that the herein investigated systems exhibit a high degree of tunability and substantially larger dielectric constants as expected for MOFs in general. The temperature dependency of κ obeys the Curie-Weiss law. In addition, the influence of dipolar linkers on the electric field induced breathing behavior was investigated. With increasing dipole moment, lower field strength are required to trigger the contraction. These investigations set the stage for an application of such systems as dielectric sensors, order-disorder ferroelectrics or any scenario where movable dipolar fragments respond to external electric fields.

scholarly journals Meta-Deflectors Made of Dielectric Nanohole Arrays with Anti-Damage Potential

Photonics ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 107
Author(s):  
Haichao Yu ◽  
Feng Tang ◽  
Jingjun Wu ◽  
Zao Yi ◽  
Xin Ye ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Laser Cutting ◽  
High Complexity ◽  
Damage Potential ◽  
Optical Components ◽  
Nanohole Arrays ◽  
Intense Light ◽  
Polarization Of Light ◽  
Air Hole

In intense-light systems, the traditional discrete optical components lead to high complexity and high cost. Metasurfaces, which have received increasing attention due to the ability to locally manipulate the amplitude, phase, and polarization of light, are promising for addressing this issue. In the study, a metasurface-based reflective deflector is investigated which is composed of silicon nanohole arrays that confine the strongest electric field in the air zone. Subsequently, the in-air electric field does not interact with the silicon material directly, attenuating the optothermal effect that causes laser damage. The highest reflectance of nanoholes can be above 99% while the strongest electric fields are tuned into the air zone. One presentative deflector is designed based on these nanoholes with in-air-hole field confinement and anti-damage potential. The 1st order of the meta-deflector has the highest reflectance of 55.74%, and the reflectance sum of all the orders of the meta-deflector is 92.38%. The optothermal simulations show that the meta-deflector can theoretically handle a maximum laser density of 0.24 W/µm2. The study provides an approach to improving the anti-damage property of the reflective phase-control metasurfaces for intense-light systems, which can be exploited in many applications, such as laser scalpels, laser cutting devices, etc.

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