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Reflectance of superconducting MgB2 thin films (Tc≈35 K) has been measured in a broad spectral range from 30 to 110,000 cm−1. A typical plasma edge with a reflectance minimum at 15,000 cm−1 has been found. In the far-infrared region we observe a pronounced rise of the reflectance below 60 cm−1, which appears below Tc and can be associated with superconducting state. The temperature-dependent complex conductivity at infrared frequencies has been determined. The real and imaginary parts of the conductivity below Tc show a temperature evolution, which is characteristic for superconducting gap opening (decrease in σ1 and rise in σ2). [Copyright &y& Elsevier]

Abstract: Optical data obtained for a-Si:H films by ellipsometry and spectrophotometry in the wide photon energy range 0.046–8.9eV are fitted using the analytical dispersion models based on the application of the sum rule. The models include all absorption processes ranging from phonon absorption in IR region to core electron excitations in X-ray region. They take into account the existence of extended and localized states of valence electrons and distinguish transitions to conduction band and higher energy electron states. It is demonstrated that a combination of optical measurements over the wide range, combined with reasonable assumptions about the optical response in regions where no experimental data are available can lead to dispersion models enabling to determine the mass density of the film. Comparing the density of states determined by tight-binding method with that obtained from optical data, it is shown that an excitonic effect is significant in a-Si:H and causes a redistribution of transition probability from higher energies to the broad peak centered at 3.5eV. Moreover, it is suggested how to apply the sum rule in the commercial ellipsometric software implementing the Tauc–Lorentz model. [Copyright &y& Elsevier]

Optical and biomedical properties of diamond-like carbon (DLC) films of various sp, sp bonds were studied. The layers were prepared by pulsed laser deposition (PLD) for laser energy densities from 4 J cm to 14 J cm. The percentage of sp and sp bonds was calculated using X-ray photoelectron spectroscopy (XPS). In dependence on density the films contained up to 70 % of sp bonds. Optical properties were measured using spectroscopic ellipsometry in region from 250 nm to 1000 nm ( n=2.6-2.7; k=0.07-0.25) and by transmission measurement (from 200 nm to 1100 nm). The adhesion and growth of human fibroblasts and keratinocytes of DLC films were tested in vitro. [ABSTRACT FROM AUTHOR]

Ablation behavior of organic polymer (polymethylmethacrylate) and elemental solid (silicon) irradiated by single pulses of XUV radiation emitted from Z-pinch, plasma-focus, and laser-produced plasmas was investigated. The ablation characteristics measured for these plasma-based sources will be compared with those obtained for irradiation of samples with XUV radiation generated by a free-electron laser. [Copyright &y& Elsevier]

Here, we demonstrate the impact of ferromagnetic layer coating on controlling the magneto-optical response. We found that the transverse magneto-optical Kerr effect (TMOKE) signal and TMOKE hysteresis loops of Ni80Fe20 thin layers coated with a Cr layer show a strong dependence on the thickness of the Cr layer and the incidence angle of the light. The transmission and reflection spectra were measured over a range of incidence angles and with different wavelengths so as to determine the layers' optical parameters and to explain the TMOKE behavior. The generalized magneto-optical and ellipsometry (GMOE) model based on modified Abeles characteristic matrices was used to examine the agreement between the experimental and theoretical results. A comprehensive theoretical and experimental analysis reveals the possibility to create a TMOKE suppression/enhancement coating at specific controllable incidence angles. This has potential for applications in optical microscopy and sensors. [ABSTRACT FROM AUTHOR]