scholarly journals Influence of magnetic confinement on the yellow excitons in cuprous oxide subject to an electric field

2018 ◽  
Vol 60 (8) ◽  
pp. 1580
Author(s):  
J. Heckotter ◽  
D. Frohlich ◽  
M. Abmann ◽  
M. Bayer
Keyword(s):  
Electric Field ◽  
Chaotic Behavior ◽  
Optical Axis ◽  
Principal Quantum Number ◽  
Exciton State ◽  
Magnetic Confinement ◽  
Dipole Interaction ◽  
Field Configuration ◽  
Threshold Field ◽  
Electric Dipole Interaction

AbstractWe study the spectrum of the yellow exciton series in crossed electric and magnetic fields. The electric field, applied along the optical axis, tilts the Coulomb potential between electron and hole, so that at sufficiently high fields exciton dissociation becomes possible, roughly when the electric dipole interaction energy exceeds the binding energy of an exciton state with principal quantum number n . For an applied voltage of U = 20 V all excitons above n = 6 are dissociated. Additional application of a magnetic field normal to the optical axis introduces magnetic confinement, due to which above a threshold field strength around B = 2.5 T the exciton lines re-emerge. The complex dispersion with increasing fields suggests quantum chaotic behavior in this crossed field configuration, so that the search for exceptional points may be promising.

ON OPTIMUM PUPIL FIELDS WITH MAXIMUM ELECTRIC FIELD COMPONENT IN FOCUS

2010 ◽  
Vol 19 (01) ◽  
pp. 189-201
Author(s):  
H. P. URBACH ◽  
S. F. PEREIRA ◽  
D. J. BROER
Keyword(s):  
Electric Field ◽  
Field Component ◽  
Optical Axis ◽  
Focal Point ◽  
Longitudinal Component ◽  
Electric Field Component ◽  
Incident Power ◽  
Entrance Pupil ◽  
Maximum Electric Field ◽  
High Na Lens

The field in the entrance pupil of a high NA lens can be optimized such that, for given incident power, the electric field component in a given direction in the focal point is maximum. If the field component is chosen parallel to the optical axis, the longitudinal component is maximized and it is found that the optimum longitudinal component is narrower than the Airy spot. We discuss how this can be used to obtain higher resolution in photolithography when a resist is used that is sensitive to only the longitudinal component. We describe a proposition for realizing such resist.

scholarly journals ELECTRO-OPTICAL SWITCHING OF THE MAIN OPTICAL AXIS OF A FERROELECTRIC LIQUID CRYSTAL SPIRAL NANOSTRUCTUREIN A PLANAR-ORIENTED DISPLAY CELL

Doklady BGUIR ◽  
2019 ◽  
pp. 21-27
Author(s):  
E. P. Pozhidaev ◽  
T. P. Tkachenko ◽  
A. V. Kuznetsov ◽  
I. N. Kompanets
Keyword(s):  
Liquid Crystal ◽  
Electric Field ◽  
Optical Switching ◽  
Optical Axis ◽  
Modulation Frequency ◽  
Light Transmittance ◽  
Weak Electric Field ◽  
Ferroelectric Liquid Crystal ◽  
Light Modulation ◽  
Small Pitch

In a known display cell with the nematic liquid crystal (NLC) and interdigital electrodes on one of the glass substrates, the “In-Plane Switching” (IPS) mode is implemented, in which the NLC main optical axis reorients in a plane parallel to substrates, providing the most correct color reproduction at different angles view, up to 178 ° horizontally and vertically. Unfortunately, the creation of interdigital metal electrodes complicates and increases the technological process cost and causes a decrease in image contrast. At the same time, experimental results and calculations based on classical electro-optics of crystals indicate that electrooptical switching in the IPS mode is a natural and intrinsic feature of a conventional (with continuous electrodes) display cell with a planar-oriented layer of the ferroelectric liquid crystal (FLC), in which the effect of the deformed (by the electric field) helix FLC nanostructure is realized (DHF effect). In such a cell, the reorientation of the main optical axis under the influence of a weak electric field also occurs in the substrate plane if the FLC has a small pitch (about 100 nm or less) and a large tilt angle of molecules in the layer (about 38 ° or more). The dependences of the FLC cell light transmittance measured in this work, confirmed the achievement of the IPS electro-optical mode in the DHF FLC cell; moreover, the light modulation frequency was 1 kHz. Thus, while maintaining all the advantages of the IPS mode known in NLC, its implementation in FLC allows additionally obtaining technological advantages and multiple increase in modulation frequency.

scholarly journals Electrorheology of a dilute emulsion of surfactant-covered drops

2019 ◽  
Vol 881 ◽  
pp. 524-550 ◽  
Author(s):  
Antarip Poddar ◽  
Shubhadeep Mandal ◽  
Aditya Bandopadhyay ◽  
Suman Chakraborty
Keyword(s):  
Electric Field ◽  
Applied Electric Field ◽  
Surface Deformation ◽  
Three Dimensional ◽  
Shear Thickening ◽  
Field Configuration ◽  
Uniform Electric Field ◽  
Surface Tension Gradient ◽  
Drop Surface ◽  
Flow Perturbation

We investigate the effects of surfactant coating on a deformable viscous drop under the combined action of shear flow and a uniform electric field. Employing a comprehensive three-dimensional approach, we analyse the non-Newtonian shearing response of the bulk emulsion in the dilute suspension regime. Our results reveal that the location of the peak surfactant accumulation on the drop surface may get shifted from the plane of shear to a plane orthogonal to it, depending on the tilt angle of the applied electric field and strength of the electrical stresses relative to their hydrodynamic counterparts. The surfactant non-uniformity creates significant alterations in the flow perturbation around the drop, triggering modulations in the bulk shear viscosity. Overall, the shear-thinning or shear-thickening behaviour of the emulsion appears to be greatly influenced by the interplay of surface charge convection and Marangoni stresses. We show that the balance between electrical and hydrodynamic stresses renders a vanishing surface tension gradient on the drop surface for some specific shear rates, rendering negligible alterations in the bulk viscosity. This critical condition largely depends on the electrical permittivity and conductivity ratios of the two fluids and orientation of the applied electric field. Also, the physical mechanisms of charge convection and surface deformation play their roles in determining this critical shear rate. As a consequence, we obtain new discriminating factors, involving electrical property ratios and the electric field configuration, which govern the same. Consequently, the surfactant-induced enhancement or attenuation of the bulk emulsion viscosity depends on the electrical conductivity and permittivity ratios. The concerned description of the drop-level flow physics and its connection to the bulk rheology of a dilute emulsion may provide a fundamental understanding of a more complex emulsion system encountered in industrial practice.

Electromagnetic and electric field configuration produced by two coils

1980 ◽  
Vol 13 (9) ◽  
pp. 804
Author(s):  
M. Dierickx ◽  
M. Hinsenkamp ◽  
L. Rybowski ◽  
F. Burny
Keyword(s):  
Electric Field ◽  
Field Configuration

Microfluidic Parallel Form Mixer Utilizing Chaotic Electric Field

2007 ◽  
Vol 364-366 ◽  
pp. 449-453
Author(s):  
Her Terng Yau ◽  
Chieh Li Chen ◽  
Ching Chang Cho
Keyword(s):  
Electric Field ◽  
Chaotic Behavior ◽  
Channel Length ◽  
Mixing Efficiency ◽  
Successful Operation ◽  
Number Systems ◽  
Flow Mixing ◽  
Reagent Consumption ◽  
Electric Filed ◽  
High Degree

The past few years, have witnessed a rapid increase in the application of microfluidic devices to chemical and biological analyses. These devices offer significant advantages over their traditional counterparts, including reduced reagent consumption, a more rapid analysis and a significant improvement in performance. Species mixing is a fundamentally important aspect of these devices since it is this mixing which generates the biochemical reactions necessary for their successful operation. Many microfluidic applications require the mixing of reagents, but efficient mixing in these laminar (i.e., low Reynolds number) systems are typically difficult. Instead of using complex geometries and/or relatively long channels, an electric field is applied to drive flow mixing in microchannels. Generally, the fluid is driven by the application of an external periodic AC electric field. However, the chaotic AC electric filed is never used to drive flow mixing in microchannels. Chaotic behavior is a very interesting nonlinear effect. In some physical systems, chaos is a beneficial feature as it enhances mixing in chemical reactions. This paper presents a numerical investigation of electrokinetically-driven flow mixing in microchannels with chaotic electric field. The simulation results show that the application of a chaotic external field enables a reduction in the mixing channel length and a high degree of mixing efficiency. It is shown that a mixing performance as high as 90% can be achieved by chaotic external electric field.

ELECTRIC FIELD-ASSISTED RELAXATION OF THE CHARGE DENSITY WAVES IN K0.3MoO3

2007 ◽  
Vol 21 (27) ◽  
pp. 1863-1867 ◽  
Author(s):  
SONG YUE
Keyword(s):  
Electric Field ◽  
Charge Density ◽  
Charge Density Waves ◽  
Voltage Characteristic ◽  
Metastable States ◽  
Threshold Field ◽  
Density Waves ◽  
Current Voltage Characteristic ◽  
Current Voltage ◽  
Ohmic Conductivity

The evolution of the current-voltage characteristic in K 0.3 MoO 3 was observed intuitively with the presence of current cycling. No variation of the ohmic conductivity was distinguished, while the threshold field for the charge density waves depinning exhibited distinct enhancement with the current cycling. These results were attributed to the electric field-assisted metastable states' relaxation of the charge density waves.

Discharge Criterion along the Surface of Solid Dielectric in SF6 under High Pressure

2014 ◽  
Vol 548-549 ◽  
pp. 21-24 ◽  
Author(s):  
Daniil A. Glushkov ◽  
Alexandra I. Khalyasmaa
Keyword(s):  
High Pressure ◽  
Electric Field ◽  
Field Distribution ◽  
Electric Field Distribution ◽  
Dielectric Surface ◽  
Field Configuration ◽  
Solid Dielectric ◽  
Discharge Criterion ◽  
Sulphur Hexafluoride ◽  
Electrode Systems

This article is devoted to the formation of a mechanism of discharge along the surface of a dielectric in sulphur hexafluoride electrode systems in different configurations. The article also addresses to the calculation of the electric field distribution and criteria for increase of discharge along the dielectric surface, depending on the field configuration, pressure and heights.

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