Magnetooptic diffraction by stripe domains with thick domain walls

The Fraunhofer diffraction spectrum is derived for a stripe domain structure with the trapezoidal distribution of the M_z component of the domain magnetization. A study is made of the influence of changes in the domain structure and of the finite thickness of the domain walls on the nature of the spectra. Phase relationships resulting in disappearance of certain diffraction orders from the spectrum are investigated. A qualitative investigation is made of the diffraction spectrum of an isolated domain wall.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 104–109, August, 1980.     

基于磁光调制偏振光的空间方位失调角高精度测量新方法

调制偏振光可以作为方位信息的载体,实现方位角度信息的传递,在军事、航天和生物医药等领域有广泛的应用前景.阐述了基于磁光调制偏振光的方位失调角测量原理,分析了现有测量原理中的误差来源.为了从理论方法上提高测量精度,提出了直接计算的方法,将磁光调制后的光强信号直接进行取极值点处理,建立了失调角与极值点之间的方程,详细分析了...     

Vibration and the Kerr effect

The theory of the Kerr effect (electric birefringence) is developed with explicit inclusion of molecular vibration. When the theory is applied to CHCl₃ and CHF₃, it is found that terms with a vibrational origin are an important component of the β-hyperpolarizability extracted from temperature-dependent Kerr studies. It is concluded that these vibrational terms partly account for the difference between β obtained from second-harmonic-generation experiments and from the Kerr constant.     

Saturation of the all-optical Kerr effect

Saturation of the intensity dependence of the refractive index is directly computed from ionization rates via a Kramers-Kronig transform. The linear intensity dependence and its dispersion are found to be in excellent agreement with complete quantum mechanical orbital computations. Higher-order terms concur with solutions of the time-dependent Schr?dinger equation. Expanding the formalism to all orders up to the ionization potential of the atom, we derive a model for saturation of the Kerr effect. This model widely confirms recently published and controversially discussed experimental data and corroborates the importance of higher-order Kerr terms for filamentation.     

Diffractional enhancement of the Kerr magnetooptic effect

The results of investigations of the transverse Kerr effect on an array of thin magnetic strips deposited on a silicon substrate are reported. The periodic structure of the sample gives rise to diffraction. It is observed that under certain experimental conditions the magnitude of the effect measured in diffracted beams is much greater than the maximum value for a sample with a uniform surface. Pis’ma Zh. éksp. Teor. Fiz. 66, No. 7, 466–469 (10 October 1997)     

Magnetooptical Kerr effect of Fe-gratings

The magnetooptical Kerr effect in longitudinal configuration is used to measure hysteresis loops of ferromagnetic Fe-gratings grown on Al₂O₃ at different orders of diffraction. At even order of diffraction the hysteresis loops exhibit anomalies which can be attributed to the interference of the magnetic and non-magnetic parts of the grating. The Kerr angle in saturation increases linearly with the order of diffraction.     

横梁弯曲衍射法测玻璃杨氏模量的改进

设计、制作了横梁弯曲衍射法测物质材料的杨氏模量仪器,并利用单缝衍射测量了火石玻璃挠度的变化,实现了螺旋加力装置配合拉力传感器对拉力连续、稳定控制.     

Kinetics of optical Kerr effect induced by picosecond laser pulses

By use of a double beam technique, we were able to observe, in the OKE dynamics of many non saturated organic compounds, a very fast decay response superimposed upon the much slower decline of the usual effect of molecular origin.     

Saturation of the all-optical Kerr effect in solids

We discuss the influence of the higher-order Kerr effect (HOKE) in wide bandgap solids at extreme intensities below the onset of optically induced damage. Using different theoretical models, we employ multiphoton absorption rates to compute the nonlinear refractive index by a Kramers-Kronig transform. Within this theoretical framework we provide an estimate for the appearance of significant deviations from the standard optical Kerr effect predicting a linear index change with intensity. We discuss the role of the observed saturation behavior in practically relevant situations, including Kerr lens mode-locking and supercontinuum generation in photonic crystal fibers. Furthermore, we present experimental data from a multiwave mixing experiment in BaF2, which can be explained by the appearance of the HOKE.     

Tunnelling effect of the non-stationary Kerr black hole

Extending Parikh and Wilczek＇s work to the non-stationary black hole, we study the Hawking radiation of the non-stationary Kerr black hole by the Hamilto-Jacobi method. The result shows that the radiation spectrum is not purely thermal and the tunnelling probability is related to the change of Bekenstein Hawking entropy, which gives a correction to the Hawking thermal radiation of the black hole.     

Magneto-optical Kerr effect in bilayer structures

This paper describes the magneto-optical effects and the reflectivity behaviors of bilayers based on magnetic and isotropic ()/anisotropic () layers under the condition of total internal reflection. In the framework of Green's dyadic technique, we show accurately the optical properties of anisotropic layers deposited on a substrate. We present numerical simulations which account for the variation of angle of incidence at the HeNe laser wavelength. The Kerr rotation is found to increase significantly around the optical modes in total reflection. We also discuss the importance of anisotropic effects due to the crystallization of the dielectric material () which occur in the reflectivity and Kerr rotation spectra. Received 26 January 2000     

Kerr effect in quantum dot structure

A three-level ladder QD system is used to study Kerr effect in QD structures. Inhomogenous broadening is included where it is shown to be critical in calculating Kerr effect in QDs. Signal detuning is shown to control Kerr dispersion.     

On the higher-order Kerr effect in femtosecond filaments

A recent experiment probing the electronic nonlinearity in the femtosecond filament indicated that the optical Kerr effect not only saturates but even changes its sign at high intensities and thus switches from self-focusing to a strongly defocusing regime. Here we examine, through simulations and experiment, some implications of such a behavior. We perform comparative simulations based on the standard model on one hand and on a model implementing the intensity-dependent Kerr effect on the other. Comparison with an experiment provides a strong indication that of these two Kerr-effect models the standard model is better in capturing the observed length of the filament. However, neither of the models can reproduce length and filament radius. Possible implications are discussed.     

Nonlinear Kerr effect in magnetic crystals

The reflection of an intense light wave from the boundary of a semiinfinite magnetic crystal is investigated theoretically. Expressions are obtained for the rotation angle of the polarization ellipse and the degree of ellipticity of the reflected wave as a function of the polarization of the incident radiation. The physical wave-interaction mechanisms that give rise to this effect are established. Fiz. Tverd. Tela (St. Petersburg) 41, 656–659 (April 1999)     

Optical Kerr effect in supercooled water

We present molecular dynamics simulations of the optical Kerr effect in liquid and supercooled water and compare with recent time-resolved Kerr spectroscopy measurements [R. Torre, Nature (London) 428, 296 (2004)]. The short time features of the Kerr response, characterized by peaks near 15, 60, and 160 fs, are weakly temperature dependent. The long-time decay is well described by a stretched exponential with a nearly constant stretch parameter and relaxation times that follow a power law approximately (T-T(S))(-gamma), with T(S)=198.3 K and gamma=2.35. Our findings are discussed in the light of the spectroscopy data and previous simulation analyzes of the structural relaxation in supercooled water.     

The even-odd effect in the Kerr effect for nematic homologous series

The Kerr effect of 4-n-alkyl- and 4-n-alkoxy-4′-cyanobiphenyls in their isotropic phase has been studied. The variation in the Kerr constant with the carbon chain length is discussed in comparison with even-odd effect in the nematic-isotropic transition temperature.     

Analysis of Kerr effect induced by temperature in Brillouin fiber-optical gyroscope

The Kerr effect induced by temperature variation in Brillouin fiber-optical gyroscope is investigated for the first time to our knowledge. It is found that the Kerr effect induced by Brillouin walk-off effect appears with the fluctuation of temperature, even the pump frequency is locked to the resonance of the resonator. The relation between the beat frequency bias and temperature variation is obtained.     

Distortions of the statistical distribution of Barkhausen noise measured by magneto-optical Kerr effect

In magneto-optical Kerr measurements of the Barkhausen noise, a magnetization jump ΔM due to a domain reversal produces a variation ΔI of the intensity of a laser beam reflected by the sample, which is the physical quantity actually measured. Due to the non-uniform beam intensity profile, the magnitude of ΔI depends both on ΔM and on its position on the laser spot. This could distort the statistical distribution p(ΔI) of the measured ΔI with respect to the true distribution p(ΔM) of the magnetization jumps ΔM. In this work the exact relationship between the two distributions is derived in a general form, which will be applied to some possible beam profiles. It will be shown that in most cases the usual Gaussian beam produces a negligible statistical distortion. Moreover, for small ΔI the noise of the experimental setup can also distort the statistical distribution p(ΔI), by erroneously rejecting small ΔI as noise. This effect has been calculated for white noise, and it will be shown that it is relatively small but not totally negligible as the measured ΔI approaches the detection limit.