Temperature dependence of the optical rotatory power (ρ) along the optical axis of pure and deuterated Rochelle salt single crystals has been given. Three phases of both crystals were examined and found to be optically active. The relation between spontaneous electrogyration (ρ_s) and spontaneous polarization (P_s) can be described by {ρ_s}∝P_s^2. Moreover, the antipolar domains of pure and deuterated ferroelectric Rochelle salt crystals were found of the rotation twin-type not occurring in the enantiomorphic form, in contrast to those in other ferroelectric crystals, e.g., TGS-type and Pb_5Ge_3O_{11}.
The paper reports results of a study of optical activity and ferroelectric properties of rejuvenated and aged deuterated triglycine sulphate crystals. A possibility of monitoring of the ferroelectric crystal ageing process by optical measurements was proved. A linear relation between optical rotatory powerρ and spontaneous polarization P_s was confirmed for aged and rejuvenated deuterated triglycine sulphate crystals.
In this work gasochromic effect in TiO_{2} thin films doped with palladium and tantalum (without catalyst film) have been described. The results have shown that in nanocrystalline TiO_{2}:(Ta, Pd), with anatase structure, the film colorization effect in alcohol presence was observed. Both colorization and also bleaching effect were stable and thermally activated.
Linear dichroism, dichroic ratio, contrast ratio and order parameters of Sudan III/PMMA guest-host thin films have been investigated with visible polarized laser light. Dichroism increased in an exponential fashion with increase of the pump intensity. Light-induced dichroism and polar order of the dye molecules within the polymer network were reversible. These parameters showed fast increase in their values in an exponential fashion as the pumping process takes place. Also, they decay rapidly in an exponential fashion when the pump light is cut off. Photoisomerisation and polar orientation are dependent on both the molecular structure of the dye and polymer. Two forms of Sudan III molecules (trans and cis) are responsible for the interaction with laser light and forming an anisotropic structure inside the PMMA/Sudan III films. However, there is another set of forms of the dye (keto and enol) has to be considered, which may contribute to dichroism.
The values of electronic polarizabilities of La³⁺, Ga³⁺, Si⁴⁺, O²¯ ions are specified using new experimental data about optical activity of La₃Ga₅SiO₁₄ crystals. A calculation technique based on the dipole electron shifting model is applied to estimate linear electrooptic coefficients for the La₃Ga₅SiO₁₄. Wavelength dependences of the both linear electro-optic tensor components r₁₁ and r₄₁ are calculated.
A study of magneto-optical circular birefringence of human serum from healthy subjects and cancer patients was performed. Significant differences in the magnetic field induced change of the natural optical activity of serum from healthy blood donors and neoplasmic patients were noted. The natural optical activity of blood is positive, irrespective of the donor health status, whereas the magnetic field induced (B > 10T) change in the natural optical activity of the serum from cancer patients is negative while that from healthy donors is positive. The value and sign of the characteristic magneto-optical marker of human serum was discovered in a study of the influence of very high magnetic fields on chiral media and interpreted on the basis of the recent developments in the theory of magnetic field induced optical circular birefringence in the media revealing natural optical activity. The blood serum is a chiral medium.
The effect of dextran concentration, pH, temperature, and urea on the conformation of dextran chain in saline solution were studied. Two characteristic concentrations for both dextrans were observed. One with c_1≈0.02 g/dL and second with c_2∼2 g/dL which may be related with aggregation and overlapping processes of polymer chains, respectively. The mean optical polarizability for dextran polysaccharides were discussed in relation to their radius of gyration. Preliminary results of the Faraday effect dispersion and their temperature dependence is also presented.
This paper reviews the experimental and theoretical results obtained during work on the modern semiconductor devices employing one-dimensional photonic structures. After short review of the physical features of structures consisting of 1D stack of the alternating high and low index layers, particular attention will be given to unique features of the devices employing microcavities: resonant cavity LEDs, resonant-cavity enhanced photo-detectors, vertical cavity surface emitting lasers, and also vertical external cavity surface emitting lasers. At the end the semiconductor saturable absorber mirrors are discussed.
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