Cotton-Mouton Effect Research Articles

Magneto-optical Cotton—Mouton effect of molecular oxygen. A comparison

Measurements of the magneto-optical Cotton—Mouton effect at 632.8 nm of O 2( 3Σ) over a range of temperature (≈299–464 K) and pressure (up to 613 kPa) are reported and analysed. The study enables a useful comparison to be made of data obtained under different conditions by the two groups that have undertaken systematic measurements of this effect. Agreement between the experimental results and also the derived molecular properties is found to be satisfactory.

Hypermagnetizability anisotropy (Cotton–Mouton effect) for H2 and D2

Explicitly electron-correlated wave functions have been used to calculate the hypermagnetizability anisotropy (Δη) for H2 and D2. This property is the essential feature of the birefringence of a material in the presence of a magnetic field (the Cotton–Mouton effect). The calculations were carried out in the framework of perturbation theory and both dispersion and vibrational effects were fully taken into account. A detailed analysis of our results is made and it is concluded that electron correlation and ‘‘pure’’ vibrational effects are less important than vibrational averaging and dispersion. The experimental results are only in fair agreement with our theoretical ones.

Waveguide optical isolator: a new design

A new design of a thin film waveguide optical isolator is described. It is composed of a nonreciprocal mode converter by the Faraday effect, a reciprocal mode converter by the Cotton-Mouton effect, an integrated mirror, and TE-mode selectors. Its mode transfer matrices are derived. Numerical calculations show that wider tolerances of the film parameters and smaller dimensions are obtained compared with the ordinary tandem type waveguide isolators without the integrated mirror. This structure is free of the problem of the localized control of the directions of the magnetization, which has been required for the ordinary tandem type waveguide isolator.

Magnetic and electric anisotropy of the P=O and P=S bonds relative to the Cotton-Mouton and Kerr effects

The Cotton-Mouton and Kerr effects were used to determine the molecular magnetic and electric anisotropies of the hexamethyl triamides of phosphorous, phosphoric, and thiophosphoric acids. The anisotropies of the phosphoryl and thiophosphoryl groups were calculated. The magnetic anisotropies of these bonds depend on the immediate environment at the phosphorus atom and correlate linearly with theσP reactivity constant.

Cotton-Mouton effects, magnetic hyperpolarizabilities, and magnetic anisotropies of the methyl halides. Comparison with molecular Zeeman and high-field NMR spectroscopic results

Measurements of the vapor-phase Cotton-Mouton effects of methyl fluoride, methyl bromide, and methyl iodide are reported. Analysis of the results, in conjunction with those of an earlier study of methane and methyl chloride, shows that in the series CH{sub 3}X (X = H, F, Cl, Br, I) the magnetic hyperpolarizabiity anisotropy, which is related to the quadratic response of the molecular polarizability to a magnetic field, is positive in sign and roughly proportional in magnitude to the mean polarizability. The magnetic anisotropies (10{sup 29}{Delta}{sub {chi}}/J T{sup {minus}2}) found for methyl chloride,methyl bromide, and methyl iodide (CH{sub 3}Cl, {minus}15.0 {plus minus} 1.3; CH{sub 3}Br, -15.1 {plus minus} 0.8; CH{sub 3}I, {minus}18.0 {plus minus} 1.5) are compared with values obtained by the molecular Zeeman and high-field {sup 2}H NMR spectroscopic methods.

Optical-magnetostatic wave coupled-mode interactions in garnet heterostructures

Optical-magnetostatic wave coupling is considered theoretically in a five-layer structure consisting of three thin films, a cover, and a substrate. Two of the thin films are magnetic and are optimized separately for microwave and optical properties. The optical mode analysis permits the layers to be anisotropic provided the permittivity tensor is diagonal in the problem coordinate system. The magnetooptical properties are treated as a perturbation. Both Faraday and Cotton-Mouton effects are included. Coupled-mode theory is applied to the optical modes in this geometry for the general case of noncollinear propagation. The extra degrees of freedom provided by two magnetic films make it possible to adjust the microwave parameters so that the operating point is near the susceptibility resonance of the optical guiding layer, thereby enhancing the magnetic response of this layer. >

Linear magnetic birefringence measurements of Faraday materials.

Measured values of the linear magnetic birefringence (Cotton-Mouton) coefficients of several Faraday-active materials (${\mathrm{Tb}}^{3+}$, ${\mathrm{Ce}}^{3+}$, and ${\mathrm{Pr}}^{3+}$ rare-earth composites) are presented. These coefficients are compared with the same coefficients measured for diamagnetic materials: ZnSe, and the liquid solvents benzene, chloroform, acetone, and water. Relatively large Cotton-Mouton coefficients, which have a strong dependence on the paramagnetic susceptibility and concentration of rare-earth ions present in these materials, have been observed for the paramagnetic Faraday materials. Difficulties introduced into the measurement of small Cotton-Mouton effects by misalignment and/or an inherent linear birefringence of a crystalline sample are discussed.

Solution-state conformation of 1,1′-binaphthyl. A Kerr and Cotton—Mouton effect study

Experimental infinite-dilution molar Kerr and Cotton—Mouton constants at 298 K are reported for 1,1′-binaphthyl as a solute in carbon tetrachloride or benzene. Analysis of the results in terms of the group-additivity model of the polarizability and magnetizability shows that the dihedral angle in the effective solution-state conformation of the molecule is approximately 90°. An alternative view of the conformational behaviour, based on free rotation across a broad potential well, also provides an acceptable interpretation of the experimental data.

Cotton-Mouton Spectrum in Cobalt-Substituted Magnetic Garnet

Spectra of the Cotton-Mouton effect and Faraday rotation in cobalt-substituted magnetic garnet films were measured at wavelengths between 0.5 and 2.0 ?m using a piezobirefringent modulator. Experimentally measured spectra were compared with those obtained by theoretical analysis within the framework of the ligand field theory. Satisfactory agreement between experiment and theory was obtained for a reasonable set of parameters.

Cotton-Mouton Effect in Monodisperse Suspensions of Liquid Crystals

Abstract The collective Cotton-Mouton (C-M) effect in the system of micron-size liquid-crystal droplets freely suspended in the isotropic liquid is studied experimentally and theoretically. The collective C-M constant in liquid-crystal suspensions is found to be from 104 to 108 times higher than the respective “molecular” C-M constant in the isotropic phase of the same substance. These large values cause the saturation in the C-M effect at relatively low magnetic fields. Using the generalized nth order Langevin's functions L, n the statistical therory is presented for the collective C-M effect in the monodisperse liquid-crystal suspensions. As a result, the induced birefringence is obtained in the form Δn = 1/2(Δn)∞ (3L 2 – 1), where (Δn)∞ is the induced birefringence at saturation. The collective C-M constant is C c = CN s S g where N 8 is the number of molecules in the droplet, S 8 is the orientational order parameter of the long molecular axes in the droplet, and C is the “molecular” C-M constant. The ...

Ｃｏ置換磁性ガーネットにおけるコットンムートン効果のスペクトル

Spectra of the Cotton-Mouton effect and the Faraday rotation were measured in cobalt-substituted magnetic garnet films between 0.5 and 2.0μm using a piezobirefringent modulator. The experimental spectra were compared with those obtained by theoretical analysis in the framework of the ligand-field theory. A satisfactory agreement was obtained between experiment and theory with a reasonable set of fitting parameters.

Magnetic anisotropy of the unshared electron pair of phosphorus and the P-O, P=O, and P=S bonds in 2-methoxy-1,3,2-dioxaphosphorinanes

1. The Cotton-Mouton effect and1H NMR spectral data of 2-methoxy-2-X-1,3,2-dioxaphosphorinanes were used to evaluate the tensor of the magnetic susceptibility of the phosphorus unshared electron pair. The anisotropy of this tensor is positive. 2. The absolute magnetic anisotropies of the P-O, P-F, P-Cl, P=O, and P=S bonds were calculated. As in the case of the optical anisotropy, the magnetic anisotropy of the P=O and P=S double bonds is not contant and depends on the immediate environment.

Magnetooptical properties in the anilinium series using Cotton-Mouton effect data

1. From the refractometry, static magnetochemistry and magnetic birefringence, data (the Cotton-Mouton effect) the different effect of ammonium and trimethyl ammonium substituents on the polarizability and magnetic susceptibility of the aromatic ring was established. 2. In primary anilinium salts the action of the positive charge is not large and amounts to some isotropic compression of the electron shell. The positive charge of the corresponding quaternary salts induces depression both of the total and of the anisotropic magnetooptical properties.

Anisotropy of the linear magnetic birefringence in erbium iron garnet

Linear magnetic birefringence (LMB or the Cotton–Mouton effect) measurements have been performed on single crystals of erbium iron garnet (ErIG) in the 4.2–300-K temperature range at 1.15 μm wavelength in magnetic fields up to 20 kOe, applied along the three cubic crystallographic directions. Light propagation was parallel to the [1̄10] direction. Except for the [110] direction at low temperatures the LMB is proportional to the internal field, and a strong anisotropy is observed in the whole temperature range. At the compensation temperature (80 K) the ‘‘LMB susceptibilities’’ change sign and are found to be proportional to the inverse of the temperature square in a wide range of temperatures. A macroscopic analysis is presented in terms of electric dipole contributions: Thesecond-order magneto-optical coefficient of the Er3+ is deduced in the spontaneous state.

Vapor-phase Cotton-Mouton effects of methane, methyl chloride, chloroform, and carbon tetrachloride

Vapor-phase Cotton-Mouton effects of methane, methyl chloride, chloroform, and carbon tetrachloride

The magnetic hyperpolarizability anisotropy of molecular hydrogen

The Cotton-Mouton effect of gaseous hydrogen has been measured with HeNe laser radiation in the temperature range between −86 and 129°C using pressures up to 200 bar. The data were reduced to the zero-density limit by means of a second-order virial expansion. Calculating the temperature-dependent contributions and fitting to the constant term leads to the magnetic hyperpolarizability anisotropy Δη = (4.2 ± 0.5) × 10 −43cm 3G −2.

Dynamical conversion of optical modes in garnet films induced by ferrimagnetic resonance

It is demonstrated that ferrimagnetic resonance can be applied to induce a dynamical conversion of optical modes in a magnetic garnet film. The fundamental and first-harmonic Fourier components of the converted mode are measured as a function of frequency and bias field; a dynamical conversion efficiency of 2% is obtained. The amplitude of the first harmonic depends very critically on the orientation of the magnetization with respect to the film normal. The results are confirmed by calculations on the basis of Faraday rotation and Cotton–Mouton effect.

Induced birefringence and dielectric polarization in fluids of non-polar ellipsoids

The local amplitude of an applied electric field polarizing a fluid comprising non-spherical molecules has components which depend on the average polarization of the sample and fluctuate with the molecular orientation. In isotropic fluids only the contraction of these fluctuations with the anisotropic part of the molecular polarizability gives a non-vanishing contribution to the dielectric polarization. In anisotropic fluids the angular average of these fluctuations of the electric field is non-vanishing and is of the same order of magnitude as the Lorentz field correction to the electric field. It contributes in all orders of the density to the dielectric virial expansion and to the molar coefficients of induced birefringence. It can serve as an explanation for the observation that the local field factor which best describes the density dependence of the Cotton-Mouton effect of CO 2 is 1 3 (ϵ + 2) and not [ 1 3 (ϵ + 2)] 2, as required by the classical Born-Langevin theory.

Steric structure of some 2-halogenated ethylbenzenes

1. With the complex use of the methods of dipole moments, the Kerr effect, the Cotton-Mouton effect, and molecular mechanics, it was shown that the 2-halogenated ethylbenzenes studied in solutions of CC14 are an equilibrium mixture of approximately equally populated trans and gauche retainers on the C-C bond. 2. In both conformations, the plane of the aromatic ring is close to shielding of the C-H bond.

Magnetic birefringence measurement in hydrogen and deuterium gases

The first measurement of the magnetic birefringence (Cotton–Mouton effect) in molecular hydrogen and deuterium has been performed. The Cotton–Mouton constant of H2 and D2 has been measured at room temperature, atmospheric pressure, and for λ=514.5 nm. Comparison with theoretical calculations shows very good agreement in both cases.