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Topic: Kerr effect


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In the News (Mon 24 Jun 19)

  
  2.0 Magneto Optic Kerr Effect (MOKE) - Growth And Study Of Magnetostrictive FeSiBC Thin Films For Device Applications
The magneto optical effects are characterised by the Kerr effect being proportional to the magnetisation.
In the longitudinal and polar Kerr effects (Fig.
Kerr images obtained using the longitudinal effect (sensitive to the magnetisation in the horizontal axis), and the transverse Kerr effect (sensitive to the magnetisation in the vertical axis).
www.study-on-line.co.uk /whoami/thesis/chap2.html   (9982 words)

  
 Kerr, John   (Site not responding. Last check: 2007-10-16)
Kerr was born in Ardrossan, Ayrshire, and studied at Glasgow.
The effect was strongest, he found, when the plane of polarization was 45° to the field, and zero when perpendicular or parallel.
The effect depended on the position of the reflecting surface with respect to the direction of magnetization and to the plane of incidence of the light.
www.cartage.org.lb /en/themes/Biographies/MainBiographies/k/Kerr/1.html   (206 words)

  
 Kerr effect - Wikipedia, the free encyclopedia
The Kerr effect or the quadratic electro-optic effect (QEO effect) is a change in the refractive index of a material in response to an electric field.
It is distinct from the Pockels effect in that the induced index change is directly proportional to the square of the electric field instead of to the magnitude of the field.
The Kerr electro-optic effect, or DC Kerr effect, is the special case in which the electric field is a slowly varying external field applied by, for instance, a voltage on electrodes across the material.
en.wikipedia.org /wiki/Kerr_effect   (1094 words)

  
 Electro-optical (Kerr, Pockels, and Faraday effect)   (Site not responding. Last check: 2007-10-16)
Often used to create extremely high speed shutters, the Kerr effect is an anisotropic change in the index of refraction of a substance in response to an electric field.
The problems with a Kerr Cell are: nitrobenzene is a volatile solvent which is remarkably toxic; the effect is proportional to the square of the E-field, which is no problem for a shutter application, but not as appropriate for a measurement application.
The Pockels effect is similar to that of the Kerr effect, except that the change in index is linearly proportional to the electric field.
home.earthlink.net /~jimlux/hv/eo.htm   (728 words)

  
 Kerr Cell   (Site not responding. Last check: 2007-10-16)
The magnetic effect showed that a rotation of the plane of polarisation of light occured on reflection from the polished pole of a magnet.
The electro-optic effect was utilised in early television instruments as a means of modulating a beam of light electrically; one of the present day applications is in the field of high speed photography where a Kerr cell is used as the shutter, giving speeds as short as 100 nanoseconds.
Kerr applied the output from an induction coil to two metal probes inserted in the holes, to observe this effect.
www.elec.gla.ac.uk /groups/opto/Kerr.html   (593 words)

  
 Kerr Effect -- from Eric Weisstein's World of Physics
The development of birefringence when an isotropic transparent substance in placed in an electric field.
It is used in constructing Kerr cells, which function as variable wave plates with an extremely fast response time, and find use in high-speed camera shutters.
Because the effect is quadratic with respect to E, is sometimes known as the quadratic electrooptical effect.
scienceworld.wolfram.com /physics/KerrEffect.html   (118 words)

  
 verzamelde MOKE documenten
The Magneto-optic Kerr effect (MOKE) and the Faraday effect correspond to a change in the intensity or polarisation state of light either reflected from (Kerr) or transmitted through (Faraday) a magnetic material.
The simplist and strongest of the effects is the rotation of polarization of reflected light when normally incident on a body which is magnetized perpendicularly to the reflection surface.
By plotting the measured Kerr signal against the field applied to the sample during a sweep, the hysteresis loop for a given material may be obtained.
staff.science.uva.nl /~jfpeters/MOKE   (1654 words)

  
 Magneto-Optics Research
These effects are generally catagorized into two phenomena, the Faraday Effect which occurs when electro-magnetic radiation is transmitted through a magnetized media, and the Kerr Effect which deals with reflections from the magnetized media.
The Magneto-Optical Kerr Effect (MOKE) is further catagorized by the direction of the magnetization vector with respect to the reflection surface and the plane of incidence.
In the longitudinal effect the magnetization vector is parallel to both the reflection surface and the plane of incidence.
www.amri.uno.edu /kstokes/mo.html   (779 words)

  
 ISTG Research - Kerr spectroscopy   (Site not responding. Last check: 2007-10-16)
Of this 100 µW, only about 1 µW is the Kerr signal to be measured and that signal must be resolved in at least a few hundred discrete levels.
Therefore, the modulation system and a Lock-in amplifier (phase sensitive detection) is used to lift the Kerr rotation and ellipticity signal from the noise.
Kerr rotation and ellipticity for a thick polished Ni-film as a function of wavelength.
utep.el.utwente.nl /smi/content/facilities/mokerr.htm   (415 words)

  
 LBNL MSD - Alivisatos/Nanocrystal Diode   (Site not responding. Last check: 2007-10-16)
The Kerr effect is a measure of the rotation of linearly polarized light by the magnetism of the material.
Kerr effect measurements have, until now, been restricted largely to visible light.
By tuning the ALS soft x-ray source to the appropriate core transition, the team was able to measure the Kerr effect of the Fe or Cr layers separately layers only (see figure).
www.lbl.gov /msd/PIs/Kortright/95/Mag95Hi.html   (477 words)

  
 Kerr Electro-Optic Effect Formal Report
The theoretical mechanism which produces the Kerr electro-optic effect is the reorientation of the material's molecular structure/lattice by the applied electric field; this reorientation is described by equation (2).
The cause of the Kerr effect is therefore a reorientation of the molecular structure of the material to one that is skewed in some manner as to be more conducive to producing optically active effects.
In considering the DC Kerr effect, one does not have to be concerned with response time, because a varying electric field is applied to the Kerr material the response time is usually on the order of femto- or micro- seconds.
www.pha.jhu.edu /~mstone/Kerr/kerrpaperentire.html   (3779 words)

  
 OPTICAL KERR EFFECT
The Kerr effect, in geometric optics, is an extension of laws of the light refraction at the time of its propagation in transparent materials with variable refractive indices.
This effect took lately a considerable importance in the Industry of telecommunications with optical fibers.
The Kerr effect is used to avoid the chromatic scattering at the time of the transmission of light.
perso.wanadoo.fr /lempel/effet_Kerr_optique_uk.htm   (548 words)

  
 Magneto-Optical Kerr effects
It is convention to refer to effects in reflection as Kerr effects and in transmission as Faraday effects.
In the longitudinal case the magnetisation vector is in the plane of the surface and parallel to the plane of incidence.
The effect is simple and occurs for radiation incident in the P-plane (E-vector parallel to the plane of incidence) or the S-Plane (E-vector perpendicular to the plane of incidence).
www.qub.ac.uk /schools/SchoolofMathematicsandPhysics/con/magnetics_group/magnetoptics.html   (983 words)

  
 [No title]   (Site not responding. Last check: 2007-10-16)
The methodology uses electric field induced birefringence (Kerr effect) with an improved sensitive optical measurement system and a new advanced mathematical formulation that allows calculation of electric field magnitude and direction in any electrode geometry from optical intensity measurements.
In the past, Kerr effect measurements have been limited to one or two dimensional parallel plate, coaxial cylinder, or parallel cylinder electrode geometries where the electric field direction does not change along the light path.
Kerr effect measurements could not be used with such geometries because the electric field direction varies along the light path and there was no physical and mathematical model that would relate a measured optical signal to the magnitude and direction of the applied electric field distribution.
lees.mit.edu /lees/old_files/full/projects/optica00.html   (976 words)

  
 Electrically and Magnetically Induced Optical Effects   (Site not responding. Last check: 2007-10-16)
The electro-optic effect is known as either a Pockels or Kerr effect depending on whether the induced change in refractive index is linear or quadratic respectively
The magneto-optic effect, or Faraday Effect, is similar to the electro-optic effect except a magnetic field is used in place of an electric field.
For modern electro-optic modulators, the Pockels, not Kerr, effect is used and the modulation speed is limited by the applied voltage, not the crystal.
www.u.arizona.edu /~jacobe   (838 words)

  
 ISTG Research - Kerr spectroscopy   (Site not responding. Last check: 2007-10-16)
To increase storage density, the wavelength of the laserdiodes in the applications is reducing.
Therefore it is useful to measure the Kerr effect at such wavelengths.
Furthermore, it is possible to raise the temperature of the sample up to 450°C using a special sample holder.
www.el.utwente.nl /tdm/istg/research/mokerr/mokerr.htm   (411 words)

  
 Encyclopedia of Laser Physics and Technology - self-phase modulation, SPM, Kerr effect, carrier density   (Site not responding. Last check: 2007-10-16)
In particular, this is the case in semiconductor lasers and semiconductor optical amplifiers, where a high signal intensity can reduce the carrier densities, which in turn lead to a modification of the refractive index and thus the phase change per unit length during propagation.
Comparing this effect to SPM via the Kerr effect, there is an important difference: such carrier-related phase changes do not simply follow the temporal intensity profile, because the carrier densities do not instantly adjust to modified intensities.
In effect, there is little conversion to other wavelengths, but the phase changes on the original wave can be substantial – in fact much higher than achievable with the Kerr effect.
www.rp-photonics.com /self_phase_modulation.html   (736 words)

  
 New Lake Kerr Bass Rule July 1
In less than a month, a new rule goes into effect on Lake Kerr allowing anglers to keep largemouth bass smaller than the statewide rules allow.
Lake Kerr is a popular Marion County recreational lake in the Ocala National Forest and anglers catch plenty of largemouth bass.
Biologists think the lack of plentiful fish food in Lake Kerr is one factor affecting the size structure of its bass population.
myfwc.com /whatsnew/06/northeast/lakekerrrule.html   (445 words)

  
 COLL 525 - DNA oligomers studied by the optical Kerr effect   (Site not responding. Last check: 2007-10-16)
COLL 525 - DNA oligomers studied by the optical Kerr effect
DNA oligomers studied by the optical Kerr effect
The optical Kerr effect shows promise as a technique for the analysis of nucleic acid structure despite the earlier negative result of Norden and collaborators (J. Phys.
membership.acs.org /c/coll/neworleans/P612793.HTM   (177 words)

  
 Magneto-optical Kerr effect   (Site not responding. Last check: 2007-10-16)
We use the magneto-optical Kerr effect (MOKE) to assess the magnetization behavior of our electrodeposited samples.
The longitudinal Kerr effect, which we measure using a configuration like the one shown above, yields qualitative information regarding alignment of magnetic moments in the surface plane of the sample.
To measure the magnetization component perpendicular to the sample surface, the experimental configuration must be modified so that the applied magnetic field is perpendicular to the sample.
www.yorku.ca /smorin/moke.html   (166 words)

  
 Definition: electro-optic effect   (Site not responding. Last check: 2007-10-16)
electro-optic effect: Any one of a number of phenomena that occur when an electromagnetic wave in the optical spectrum interacts with an electric field, or with matter under the influence of an electric field.
Note 1: Two of the most important electro-optic effects having application as modulation mechanisms in optical communication are the Kerr effect and the Pockels effect, in which birefringence is induced or modified in a liquid (Kerr effect) or solid (Pockels effect).
This HTML version of Telecom Glossary 2K was last generated on Wed May 8 15:36:48 MDT 2002.
www.its.bldrdoc.gov /projects/devglossary/_electro-optic_effect.html   (107 words)

  
 Enhanced Optical Kerr Effect in Dye-doped Isotropic Liquid Crystals   (Site not responding. Last check: 2007-10-16)
It is known that the Optical Kerr Effect of nematic liquid crystals can be strongly enhanced by a small amount of dye impurities if the laser field resonantly excites the dye.
We have shown that the same effect exists even if the liquid crystals are in the isotropic phase.
Our experiment showed that mixing 0.1isotropic E7 liquid led to an enhancement as large as 10, which is comparable to that found in the nematics phase of the same LC/dye mixtures.
flux.aps.org /meetings/BAPSMAR96/abs/S150003.html   (137 words)

  
 Kerr effect - Wikipedia, the free encyclopedia
Light can be modulated with these devices at frequencies as high as 10 GHz.
Some transparent crystals have also been used for Kerr modulation, although they have smaller Kerr constants.
Consider the net electric field E produced by a light wave of frequency ω togther with an external electric field E
en.wikipedia.org /wiki/Kerr_cell   (1094 words)

  
 An Accurate Method for Obtaining Surface Magnetooptic Kerr Effect Signals   (Site not responding. Last check: 2007-10-16)
We describe a method for measuring the magnetooptic Kerr effect (MOKE) which cancels also spurious signals due to Faraday rotation in the optical components and the sample itself.
The method consists of subtracting the normalized s- and p- polarization signals from each other, and takes advantage of the fact that the Faraday rotation is independent of polarization, while the MOKE signal changes sign when the polarization is changed\footnote E. Moog, C. Liu, S. Bader, and J. Zak, Phys.
This technique should be especially useful for measurements performed in cryostats and vacuum systems where the optical windows, which cause Faraday rotations, are in close proximity to the applied magnetic field and in types of magnetic films where the magnetic characterization of only the surface is of interest.
flux.aps.org /meetings/YR01/MAR01/abs/S6020011.html   (216 words)

  
 An Introduction to MOKE (Magneto-Optic Kerr Effect) and SMOKE
When a beam of polarised light reflects off a magnetised surface, the plane of polarisation of the light can slightly rotate.
This phenomenon is known as the magneto-optic Kerr effect, named after Reverend Kerr who discovered the effect in the 19th Century.
The technique is sometimes referred to as SMOKE, where the S stands for surface.
www.uksaf.org /tech/moke.html   (271 words)

  
 Kerr Microscopy   (Site not responding. Last check: 2007-10-16)
Optical microscopy using the magneto-optic Kerr effect is a well established tool for imaging magnetic microstructure.
We have built a microscope specifically for examining the thin film magnetic multilayers that we grow for our SEMPA studies of oscillatory exchange coupling.
As usual in Kerr microscopy the saturated magnetic state is used as a reference for removing topographic features as shown in these images from a NiFe thin film.
physics.nist.gov /Divisions/Div841/Gp3/Facilities/kerr.html   (163 words)

  
 Nonlinear optics : Kerr effect
Stability of spatial soliton arrays generated in a noninstantaneous Kerr medium from partially spatiotemporally coherent light
Transverse and soliton instabilities due to counterpropagation through a reflection grating in Kerr media
On the limits of validity of nonparaxial propagation equations in Kerr media
www.opticsinfobase.org /ocisdirectory/190_3270.cfm   (291 words)

  
 DYNAMIC KERR EFFECT   (Site not responding. Last check: 2007-10-16)
This book is conceived as a lecture course on the theory of dielectric and Kerr effect relaxation in molecular fluids.
The literature on the subject originates essentially from review articles which, however, are pitched at such a high level that it is very difficult for students to understand.
Analysis of Rotational Molecular Motion in Kerr Effect Relaxation
www.worldscibooks.com /physics/2493.htm   (130 words)

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