Fyzikální ústav Akademie věd ČR

Languages

Research at Department 21

Study of refraction occurring during x-ray diffraction and its applicationResearch subjects

We have developed various types of x-ray synchrotron radiation monochromators with some additional properties: focusing, collimating, beam splitting and harmonics filtering. This, so called diffractive-refractive optics, was entirely developed in our group and was published in more than 20 papers and one book. Celý text >>

Research in the field of x-ray crystal optics for synchrotron radiationResearch subjects

Research is focused on development of dynamical theory of x-ray diffraction on perfect crystals and the utilization of the results for the design and realization of new x-ray optical elements based on Si single crystals. In the collaboration with the Czech company Polovodice a.s. and by utilization of the optical laboratory and the optical work-shop of the Institute we are able to realize these elements (usually the focusing crystal monochromators). Celý text >>

Optical spectroscopy of crystals, ceramics, thin films, and nanostructures of dielectric and semiconducting materials suitable for application in optic, optoelectronic, microelectronic, acoustooptic, pyroelectric, and piezoelectric devices.Research subjects

The aim of study of photoluminescence, thermoluminescence and optical absorption in the UV, visible, and IR spectral range is to reveal intrinsic point defects and impurities, to elucidate their electronic structure, and to determine their influence on material properties. Special attention is paid to optical properties of transition metal ions serving as spectroscopic probes for study of phase transitions. Celý text >>

A "soft electronic band" and the negative thermooptic effect in strontium titanateSelected results

The optical properties of strontium titanate (SrTiO₃) single crystals were determined with spectroscopic ellipsometry in the 1–6 eV spectral region and the 4.2–300 K temperature region.New results regarding features of band edge and near band edge indirect and direct fundamental optical transitions were obtained and updated.It was shown that whereas the indirect transitions lowest in energy shift to higher energies on cooling, the energy of the stronger direct optical transitions in the region of 3.7–4.0 eV shifts to the opposite side, to lower energies , and these transitions can b Celý text >>

Spectroscopic ellipsometry applied to phase transitions in solids: possibilities and limitationsSelected results

The possibilities of in situ spectroscopic ellipsometry applied to phase transitions investigation in oxide thin films and crystals are examined in this work, along with the use of various parameters calculated from ellipsometric data (band gap energy E_g, refractive index n and surface roughness) together with the directly measured main ellipsometric angles ψ and Δ, for the detection of phase transitions.
doi: http://dx.doi.org/10.1364/OE.17.014322 Celý text >>