Polarization analysis of birefringence in uniaxially deformed silicon crystals

The birefringence induced by uniaxial compression in low-doped silicon crystals was investigated both theoretically and experimentally. The circular components of the Stokes vector in the transmission and reflectance radiation are measured as a function of external pressure by using the method based on the modulation of radiation polarization. The value of the Brewster constant was obtained for absorption (λ = 0.63 µm) and transparence (λ = 1.15 µm) regions. The obtained experimental data are in a good agreement with calculation results based on the anisotropy model of dielectric properties within the framework of the Hook law. Shown is the practical importance of the polarization analysis in researching anisotropy of dielectric properties of materials

Investigation of Al-ZERODUR interface by Raman and secondary ion mass spectroscopy

The interface of ZERODUR ceramics and thin aluminium film was investigated by Raman and secondary ion mass-spectroscopy techniques. Possible chemical reactions at the interface is briefly analyzed and compared with experimental data. Contributions of amorphous and crystalline phases of ZERODUR to Raman spectra are discussed. Keywords: ZERODUR ceramics, Raman spectra, secondary ion mass-spectroscopy. Manuscript received 19.04.05; accepted for publication 18.05.05

Spectra of the photo-electric phenomena physically differentiated on the light absorption factor

The pleochroism phenomena in photoconductivity of Ge samples and gate photoelectomotive force (photo-emf) of Si samples were experimentally investigated by a polarization modulation method. Anisotropy of dielectric properties was created by uniaxial compression. The spectral characteristics of the polarization difference describing above effects were measured. We found that: а) the pleochroism spectrum of photoconductivity is a derivative with respect to the absorption factor of a photocurrent function; b) the pleochroism spectrum of the gate photo-emf contains dichroic components, determined by the sample thickness, diffusion length of majority carriers, and layer thickness of a spatial charge

Composite film structures containg ZnS, CdS nanoparticles prepared by MOC pyrolysis at low temperatures

New composite structures containing ZnS, CdS nanoparticles were prepared with bright light-blue colour of a luminescence. The structures were formed by spraying organic solution of zinc or cadmium ditiocarbamate onto substrates at temperatures within the range 40…120°C. It was established that the film emission maximum monotonously shifts into short-wave spectral region at the decreasing substrate temperature: from 590 nm (Ts = 120°C) to 500 nm (Ts = 50°C) for ZnS and from 510 nm (Ts = 120°C) to 450 nm (Ts = 40°C) for CdS. This fact can be explained by the quantum size effect: X-ray analysis has shown that researched films contain crystalline particles of 1…5 nm size

Filter for TV and video cameras

An infrared-cut filter for TV and video cameras was calculated and fabricated. The filter contains 28 alternating SiO₂ and TiO₂ layers. The filter was calculated using the principle of unequal-thickness layers. This filter has a transmittance of 95 % in 400 to 650 nm range and 1 % in 700 to1150 nm range

Microwave-induced optical non-linearity of amino acid crystals

Changes (ΔR) of amino acid crystals infrared (IR) reflectance (R) induced by simultaneous irradiation of IR and microwaves (MW) or extremely high frequency (EHF) radiation have been observed. It was shown that under the microwave action, components of dielectric permeability tensor, εij, which is responsible for the alteration of the R, are changed. Square dependence of ΔR/R on power of EHF radiation has been observed. An attempt for explanation of the observed effect as non-linear phenomenon with participation of two EHF photons (Ωm) and one IR photon (ωi) was made. The estimation shows that the third order non-linear polarizability coefficient, χ⁽³⁾(Ωm,-Ωm, ωi), reaches the gigantic value - 10 сm/erg for α-Gly single crystal

SPR-spectroscopy of protein molecules adsorbed in microwave field

A possibility to use surface plasmon resonance (SPR) in the investigations of the microwave radiation influence upon proteins in the process of their adsorption on the gold surface and their interaction with other proteins. For the first time, this method is applied to experimental study of physical parameters of the biological molecules under the action of the weak (from 1 to 10 mW/ cm²) electromagnetic fields in real-time regime. The changes in the process of adsorption of protein on the gold at different stages of the absorption as well as the changes in the reaction of antigen-antibody were introduced under the action of microwave field. More dense layers of protein was obtained in the microwave fields resulting in the decreased contribution of non-specific and specific interactions between proteins