Showing papers on "Kerr effect published in 1976"
TL;DR: In this paper, it was shown that a single dye-laser pulse can induce a Kerr effect at Raman-shifted frequencies. But this effect was shown to induce a small fraction of the power required to produce stimulated instabilities.
Abstract: A new effect is demonstrated in which a laser pulse can be made to induce a Kerr effect only at Raman-shifted frequencies. This permitted the observation of a Raman spectrum with a single dye-laser pulse. The pulse power required is a small fraction of that required to produce stimulated instabilities. The spectral information emerges in a coherent beam, phase matching is not necessary, and spectra can be obtained at any scattering angle.
182 citations
TL;DR: In this paper, the interference between resonant and background contributions is eliminated, and undistorted line shapes are obtained using polarization technqiues based upon four-wave mixing, and specific polarization conditions will suppress all signals with the exception of those arising from Raman modes.
Abstract: Background signals which appear in Coherent anti‐Stokes Raman spectroscopy and in the Raman‐induced Kerr effect can be eliminated using polarization technqiues based upon four‐wave mixing. Specific polarization conditions will suppress all signals with the exception of those arising from Raman modes. The interference between resonant and background contributions is eliminated, and undistorted line shapes are obtained.
106 citations
TL;DR: Theoretical and experimental results for the line shape of Raman-induced Kerr effect resonances observed with elliptical pump polarization were presented in this paper, showing that the electronic contribution to the Kerr constant of benzene is 12%.
Abstract: Theoretical and experimental results are presented for the line shape of Raman-induced Kerr effect resonances observed with elliptical pump polarization. The line shape is sensitive to the ratio of the Kerr constant to the Raman tensor. Comparison of these results to those obtained by three-wave mixing reveals that the electronic contribution to the Kerr constant of benzene is 12%.
48 citations
TL;DR: In this article, a sign reversal of the Kerr effect between direct current and optical frequency fields is reported both for the pure isotropic phase and for the material in solution, when conducted over a limited temperature range.
Abstract: The Kerr effect has been studied in the nematic liquid crystal M.B.B.A. both for its isotropic phase and in solutions in CCl4. Electric and high frequency laser fields were used and both Static and Optical Kerr constants evaluated. The laser-induced birefringence has been studied as a function of temperature, time and equivalent field strength. A sign reversal of the Kerr effect between direct current and optical frequency fields is reported both for the pure isotropic phase and for the material in solution. In addition the static field studies indicated that a sign reversal in d.c. fields might be obtainable as a function of solution concentration. The studies in the isotropic phase, when conducted over a limited temperature range, indicated that the short-range-order theory proposed by de Gennes is appropriate to this system.
37 citations
TL;DR: In this article, the molar Kerr constant of cyclohexane and the n−alkanes from propane through decane were measured over the temperature range 313-461 K and pressure range 0-8 bar.
Abstract: Gas phase measurements of the molar Kerr constant, mK, of cyclohexane and the n‐alkanes from propane through decane have been made over the temperature range 313–461 K and pressure range 0–8 bar. When examined in conjunction with previous light scattering measurements our results lead to the following conclusions: hyperpolarizability contributions to mK are of the same order of magnitude as anisotropy of polarizability contributions; the assumption of the additivity of bond polarizability tensors seems to fail for the higher n‐alkanes in the gas phase; values of mK and the depolarization ratio obtained from solution measurements are much less than the gas phase values.
29 citations
TL;DR: In this paper, the relaxation time of the Kerr effect of nitrobenzene and m-nitrotoluene in various mixtures with carbon tetrachloride and various alcohols was determined using picosecond laser techniques.
28 citations
TL;DR: Characterization of the hydrodynamic relaxation spectra for the DNA's by oscillatory flow birefringence allows precise comparison between theory and the experimental Kerr effect response.
Abstract: The optical birefringence induced in DNA solutions by both oscillating hydrodynamic fields (flow birefringence) and oscillating electric fields (Kerr effect) is measured over a wide frequency range. The observed frequency response of the birefrigence is compared with theories for rigid ellipsoidal particles and for Gaussian chains. DNA at 6 × 105 molecular weight is found to exhibit rigid particle hydrodynamic behavior, while DNA at 5 × 106 molecular weight behaves like a flexible chain. Characterization of the hydrodynamic relaxation spectra for the DNA's by oscillatory flow birefringence allows precise comparison between theory and the experimental Kerr effect response. The dielectric model for DNA contains both permanent and dispersionless induced dipole moments. The dielectric behavior of DNA has the character of a permanent dipole but with anomalous low-frequency dispersion in the Kerr effect. The existing theories do not adequately describe this dispersion. A fluctuation dipole mechanism with relaxation times comparable to those associated with the hydrodynamic motion could possibly demonstrate the observed polar behavior.
28 citations
TL;DR: In this paper, an intense continuum has been generated in D 2 O by a 12 mJ, 1.06 μ single picosecond pulse obtained from a mode-locked Nd:glass laser.
23 citations
TL;DR: In this article, the temperature dependences of the extraordinary Hall effect (EHE) and the polar Kerr effect (PKE) hysteresis loops are measured in amorphous rare-earth transition metal (TM) films.
Abstract: The temperature dependences of the extraordinary Hall effect (EHE) and the polar Kerr effect (PKE) hysteresis loops are measured in amorphous rare‐earth (RE) transition metal (TM) films. The polarity of each effect corresponds to that of its TM component. The temperature dependence of Hall voltage is similar to that of the Kerr rotation angle, and, in Gd‐Co‐Mo films, it is similar to that of Co sublattice moment calculated by Hasegawa's two sublattice model. From these results, both EHE and PKE in RE‐TM films are considered to mainly associate with the TM sublattice moment.
21 citations
TL;DR: In this article, the authors characterized the magnetic properties as a function of compressive stress, σ c, parallel to the [001] direction for a 60 Hz magnetic domain.
Abstract: Demagnetized domain structures were viewed by Kerr effect and 60 Hz magnetic properties were characterized as a function of compressive stress, σ c , parallel to the [001] direction for a
16 citations
TL;DR: The Hall effect and Kerr effect in rare earth-cobalt systems are investigated theoretically and experimentally as discussed by the authors, where the Hall resistivity originates almost from the anomalous part of the rare earth component.
Abstract: Hall effect and Kerr effect in rare earth-cobalt systems are investigated theoretically and experimentally. The Hall resistivity originates almost from the anomalous part of the rare earth component. Its magnitude and temperature dependence reflect those of the magnetic moment of the rare earth. On the other hand, the Kerr rotation originates almost from the cobalt component in visible region. The Hall resistivity in the ferrimagnetic rare earth-cobalt systems, such as Gd-Co, reverses its polarity at the compensation temperature reflecting the reversal of the rare earth magnetic moment in the external field. The gradual reversal in the amorphous films is due to the inhomogeneity of the specimens.
TL;DR: In this article, an apparatus is described with which the electric vector of a suitably defined laser beams has been used to induce optical birefringence in various liquid media.
Abstract: An apparatus is described with which the electric vector of a suitably defined laser beams has been used to induce optical birefringence in various liquid media. Blue light from a low powered argon laser monitored the birefringence in the sample cell while the infrared (1.06 $\mu $m wavelength) radiation of a neodymium doped YAG laser interacted with the sample molecules to give rise to the birefringence effects. The principal object of the study was to manifest effects in dilute solutions of macromolecules. Initial attempts involved mechanically chopping the YAG beam whose power was some 20 W continuous output. Only thermal effects were observed. These experiments are outlined as they give effects which might easily be mistaken for particle orientation effects. By 'Q' switching the laser, the increased power in the beam was sufficient to induce birefringence in pure liquids and liquid crystals. Finally, when operated in a 'fixed Q' mode, the intermediate power but increased pulse duration (100 $\mu $s) enabled the optical Kerr effect to be realized in macromolecular solutions. Typical results are given for suspensions of bentonite clay and potassium hyaluronate in water.
TL;DR: In this article, the longitudinal Kerr rotation and Kerr ellipticity, and the refractive index and extinction coefficient were measured for evaporated Ni-Fe films over the entire range of composition in the alloy system.
Abstract: The longitudinal Kerr rotation and Kerr ellipticity, and the refractive index and extinction coefficient were measured for evaporated Ni–Fe films over the entire range of composition in the alloy system. The magneto-optic parameter Q=Q0exp (-iq) was discussed. Q0 was found to be proportional to saturation magnetization Ms in both the f.c.c. and b.c.c. structure composition ranges. For the f.c.c. region (100%Ni to 50%Ni) Q0=1.6×10-5Ms, while for the b.c.c. phase (pure Fe to around 30%Ni–Fe) Q0=1.2×10-5Ms. The proportional constant for the b.c.c. phase was smaller by about 25% than that for the f.c.c. phase. This result cannot be explained within the framework of the classical theory considering the motion of conduction electrons in the internal magnetic field. It is suggested that the longitudinal Kerr effect might be closely related with the electrons responsible for the spontaneous magnetization.
TL;DR: In this article, the electro-optic Kerr effect has been measured for styrene and several high molecular weight polystyrenes in dilute solution in carbon tetrachloride.
TL;DR: In this paper, it was shown that in the calculation of the contribution to the Kerr effect in polar liquids by hyperpolarizabilities, the effective field should be taken equal to the sum of the Lorentz field and the reaction field.
TL;DR: In this article, the static field Kerr electro-optic effect has been studied in solutions of the nematic liquid crystals MBBA and PCB in carbon tetrachloride and the dependence of these constants on concentration differed markedly between these two nematic materials.
Abstract: The static field Kerr electro-optic effect has been studied in solutions of the nematic liquid crystals MBBA and PCB in carbon tetrachloride. These compounds are negative and positive nematics respectively. At low field strengths, all solutions exhibited Kerr law behaviour and Kerr constants were evaluated. The dependence of these constants on concentration differed markedly between these two nematic materials. With MBBA, the birefringence and hence the Kerr constant underwent a reversal of sign from positive to negative with increasing solution concentration. With PCB, the Kerr constant was always positive. Whereas MBBA solutions always showed Kerr law behaviour for fields up to 45 kV cm-1, the PCB solutions showed deviations from this at the higher field strengths. Combinations of higher concentrations and field strengths resulted in irregular transients in the birefringence.
TL;DR: In this article, the Raman-induced Kerr effect is shown to offer significant advantages over three-wave mixing when the screening length is much smaller thanc÷[plasmon frequency].
Abstract: We compare two nonlinear optical effects which show promise of yielding directly plasmon frequencies, damping rates, and intensities in small, transient (submicrosecond) plasmas. The Raman-induced Kerr effect is shown to offer significant advantages over three-wave mixing when the plasma screening length is much smaller thanc÷[plasmon frequency]. When the screening length is much smaller than the optical wavelengths, then the former effect can yield an electron-density fluctuation spectrum with laser powers (∼MW) that are readily available.
TL;DR: In this article, a plane-wave analysis for the Voigt orientation of an applied static magnetic field − B in cubic semiconductors having ellipsoidal constant energy surfaces is given.
TL;DR: In this article, the high-frequency Kerr constants for a variety of polar liquids relative to nitrobenzene, a strong Kerr-active liquid, were measured for the first time.
Abstract: The high-frequency Kerr constants are measured for the first time for a variety of polar liquids relative to nitrobenzene, a strong Kerr-active liquid. Among the liquids investigated were aromatic compounds, ketones, and fluoroalcohols. The measurements consisted in inducing optical birefringence in the liquid samples by the intense electric fields from a Q-switched Nd:glass laser and simultaneously observing a pulsed signal through crossed polarizers using a low-power He–Ne laser as a light probe at 6328 A. Comparison of the measured and calculated optical Kerr constants for those liquids where the depolarization ratios and isothermal compressibilities were known showed satisfactory agreement. A number of liquids exhibited high-frequency Kerr constants on the order of nitrobenzene.
01 Sep 1976
TL;DR: In this article, a simple method for detection of electro-optical nonlinearities in thin films is presented, which involves an easily fabricated structure and a little practice in integrated optical techniques, and it is also possible to detect small induced variations of refractive index, using lower voltage with respect to those applied in a conventional Kerr cell.
Abstract: A simple method for detection of electro-optical non-linearities in thin films is presented. The method involves an easily fabricated structure and a little practice in integrated optical techniques. It is also possible to detect small induced variations of refractive index, using lower voltage with respect to those applied in a conventional Kerr cell. We have sucessfully tested our method using two different polymer materials as thin films. In both of these we have observed an induced ?n ? 3 10?5 with an electric field of 60 V/?, with a response time round about 300 nsec. The experimental values of induced ?n versus electric field fit very well a parabola, proving the quadratic behavior of Kerr effect.
TL;DR: In this article, a conformational equilibrium was established in which the predominant configuration is that of the inverted boat, according to the NMR data, and that of boat itself, in the case of the β-thiooxide.
Abstract: 1.
Analysis of1H NMR spectra has shown that the thiooxide obtained from the α-oxide of Δ3-carene has the two three-membered rings in the cis-configuration, while the thiooxide obtained from the β-oxide is a trans-isomer.
2.
Measurements of the1H and13C NMR spectra and the Kerr effect have shown the predominant conformation of the α-thiooxide molecule to be that of the inverted boat. In the case of the β-thiooxide, a conformational equilibrium is established in which the predominant configuration is that of the inverted boat, according to the NMR data, and that of the boat itself, according to the Kerr effect measurements.
01 Jan 1976
TL;DR: In this article, the authors established the theoretical connection between the light scattering spectrum of a medium and its (third-order) nonlinear optical susceptibility, and used this connection to obtain the nonlinear susceptibility spectra.
Abstract: We establish the theoretical connection between the light scattering spectrum of a medium and its (third-order) nonlinear optical susceptibility. This connection is used to obtain the nonlinear susceptibility spectra.
01 Feb 1976
TL;DR: In this paper, the authors considered the case of a one-hundred picosecond pulse interacting with a monoatomic gas and proposed a new mechanism which may cause self-focusing in gases.
Abstract: A new mechanism which may cause self-focusing in gases is proposed. We consider the case of a one-hundred picosecond pulse interacting with a monoatomic gas. Under these conditions of short time, low density and spherical atomic symmetry, the usual self-focusing mechanisms such as the Kerr effect may not be applicable. Since there are indications that self-focusing does occur under these conditions, one is led to seek new sources of nonlinearity in the wave equation. The one suggested here is multiphoton Raman scattering. For a sufficiently intense beam this should be a very rapid process and produce observable effects even under the afore-mentioned conditions. Our initial calculations indicate that this indeed may be the cause of self-focusing in gases.