Hafnia-yttria-alumina-silica based optical fibers with diminished mid-IR (> 2 mu m) loss

Fabrication details and basic characteristics of a set of novel multimode hafniayttria- alumina-silicate (HYAS) core-glass based fibers, one of which is co-doped with bismuth (Bi), for the mid-IR (> 2 mu m) spectral range are reported. It is demonstrated that fibers of this type possess low fundamental loss in the spectral range beyond 2 mu m, lowered by fewer times as compared to conventional silica-based ones, even at moderate (units of mol.%) co-doping with hafnium. This makes them attractive for versatile mid-IR applications. Furthermore, HYAS core-glass fiber co-doped with Bi is revealed to have all the signs of `active' (fluorescing) Bi-related centers, thus being suitable for lasing/amplifying in the nearIR spectral range. (C) 2017 Optical Society of Americ

Psychophysiological methods for the diagnostics of human functional states: New approaches and perspectives

L. S. Vygotsky in his famous methodological essay “The historical meaning of psychological crisis” (1928) emphasized the importance of studying any psychological process or state as a “whole” — that is, as characterized from the subjective and objective sides at the same time. This position is fully relevant for studying the human functional states (FSes). Today the objective psychophysiological diagnostics of human FSes in activities associated with a high risk of technological disasters (in nuclear-power plants, transportation, the chemical industry) are extremely relevant and socially important. This article reviews some new psychophysiological methods of FS assessment that are being developed in Russia and abroad and discusses different aspects of developing integral psychophysiological FS assessment. The emphasis is on distant methods of FS diagnostics: the bioradiolocation method, laser Doppler vibrometry, eye tracking, audio and video recordings, infrared thermography. The possibilities and limitations of the most popular emotion atlases — the Facial Affect Scoring Technique (FAST) and the Facial Action Coding System (FACS) — in developing distant visual-range and infrared-range systems for automated classification of facial expressions are analyzed. A special section of the article concentrates on the problem of constructing an integral psychophysiological FS index. Mathematical algorithms that provide a partition of FS indicators into different FS types are based on various methods of machine learning. We propose the vector approach for construction of complex estimations of the human FSes

Optical spectroscopy of Ce3+\mathrm{Ce^{3+}} ions in Gd3(AlxGa1−x)5O12\mathrm{Gd_{3}(Al_{x}Ga_{1−x})_{5}O_{12}} epitaxial films

Epitaxial films of Ce-doped Gd3(AlxGa1−x)5O12 with x = 0.00, 0.22, 0.31, 0.38 formula units were grown using liquid-phase epitaxy method, and their optical properties were studied. The emission of Ce3+ ions can be observed only when Al3+ ions are incorporated into the garnet structure, resulting in a shift of the 5d Ce3+ states from the conduction band to the bandgap. It is shown that the shift is caused by the cumulative effect of gradual low-energy shift of the lowest 5d level of Ce3+ and the raise of the garnet bandgap energy with increasing Al3+ concentration