Attenuated total reflection (ATR) is widely used in infrared spectral range for measurement of surface properties
of solid samples, powders, and liquids. In this paper we use a commercial Fourier-transform infrared (FTIR)
spectrometer Vertex 70v from Bruker company equipped with the ATR Golden Gate accessory from Specac.
To increase sensitivity of the method we included infrared polarizer and analyzer, which enable measurement
of the reflected amplitudes ratio and the phase differences between p- and s-polarizations in the frame of the
ATR ellipsometry. Procedure of ellipsometric angles measurement is proposed using data acquisition at several
azimuthal angles of polarizers. Spectral dependence of real polarizer extinction ratio, partial polarization of
beam coming from the interferometer and polarization sensitivity of infrared detector are presented.
Single crystals of the terbium-scandium-aluminium garnet (Tb3Sc2Al3O12) and terbium-scandium perovskite
(TbScO3) prepared using the micro-pulling down method represent important materials with potential in photonics
and optics. A method for far- and mid-infrared spectroscopy of the samples as small as 1 mm is proposed
and tested in reflection and transmission configuration. High signal-to-noise ratio and high precision are obtained
using the vacuum Fourier transform infrared (FTIR) spectrometer and a special pinhole holder. Reflectance spectra
of the materials are measured in the spectral range from 7500 to 100 cm-1 (1.3 μm - 100 μm) for the angle of
incidence of 11 degree. Optical functions were obtained by fitting of the data with the model dielectric function
consisting of Lorentz damped harmonic oscillators and fulfilling the Kramers-Kronig dispersion relations.
We have investigated the transverse magneto-optical Kerr effect (TMOKE) in thin films of ferromagnetic manganites
(La2/3Sr1/3MnO3, La2/3Ca1/3MnO3) with visible light. In addition to the standard transverse MO Kerr
effect - which is proportional to the magnetization component perpendicular to the plane of light incidence - we
have observed a strong even contribution roughly proportional to the absolute value of applied magnetic field.
It is well observed near the Curie temperature. This contribution is not the ordinary quadratic magneto-optical
effect it but is related to the magnetorefractive effect (MRE) - the optical equivalent of magnetoresistance -
which give rise a significant change of reflectivity with the applied magnetic field. This magnetorefractive effect
can exceed more than ten times the linear magneto-optical effect (MOE). This finding is against common
assumption that MRE is negligible in the visible spectral range and therefore both MRE and MOE should be
considered. Detailed analysis of measurements in various magneto-optical configurations is provided and the
method of separation of both contributions is shown. Finally we envisage the possibility to exploit this effect
in remote optical magnetic field sensor, which can be useful for nondestructive, noninvasive, and local magnetic
Tb3Sc2Al3O12-TbScO3 eutectic crystallizes in a rodlike microstructure, and its potential to exhibit photonic
bandgap has been presented tentatively. In order to model its optical properties there is a need for precise
determination of the optical properties of its component materials in a wide spectral range. Spectroscopic data
in the range from 0.6 to 6.5 eV (190-2100 nm) were obtained using spectroscopic ellipsometer UVISEL, Horiba
Jobin-Yvon. The measurement was completed with mid infrared reflection data using Bruker FTIR spectrometer
in the spectral range from 7500 to 550 cm-1. Optical functions were obtained using fitting of the data with
model dielectric function fulfilling the Kramers-Kronig dispersion relations. Obtained optical functions enable
to model the optical properties of self-organized eutectic micro- and nanostructures.
Magneto-optical (MO) Kerr effects are widely used for a thin film magnetism study. The otpical and MO properties of layer media are described through the permittivity tensor. A cubic crystal is optically isotropic and the linear MO effects are independent on the rotation of the crystal axes. On the contrary the MO effects quadratic in the magnetization are anisotropic in a medium with a cubic symmetry as well. In the paper, the anisotropy of the quadratic MO effects is discussed in the case when the magnetization lies in the plane of the layer. This configuration especially at a normal incidence is very suitable for the quadratic MO effects observations. The eigenmode equation is solved including both the linear and the quadratic terms in the permittivity tensor. The boundary conditions of the electric and magnetic fields at interface are described using 4 X 4 Yeh's matrices. The reflection coefficients form an interface between isotropic and MO media are derived including the quadratic MO terms. The quadratic MO effects observed through the conversion reflection coefficients and through the MO angles are dependent on the crystal axes orientations. The experimental measurements of the quadratic MO effects in reflection form an epitaxial bcc Fe layer are presented.
Three basic configurations are usually distinguished in calculations of the light propagation in magneto-optical media: polar, longitudinal and transverse direction of the magnetization. In these particular cases the fourth order equations for normal components of the wave vectors reduce to bi-quadratic ones. Analytic solutions of this equation are obtained also for a mixture of longitudinal and transverse effects (magnetization in the plane of interface) and for a mixture of polar and transverse effects. These configurations are discussed in details. If the magnetization is in general direction, the fourth-order characteristic equation has to be solved by using numerical methods. Permittivity tensor is considered for the case of cubic magneto-optical crystal. Its linear and quadratic terms in magnetization are included. The magneto-optical medium is described by the index of refraction and by linear and quadratic epitaxial Fe layer on MgO substrate. The magnetization component effects in general direction are studied by numeric calculations of the reflection coefficients. The mixture of the polar, longitudinal and transverse magneto-optical effects is analyzed taking into account the second order terms. The effects of the magnetization components are specified at normal incidence geometry, because in this case the calculation becomes simpler.