The spectral and holographic characteristics of classical and modified photothermorefractive glass are compared. It shows that modified photothermorefractive glass has no additional absorption bands in the blue–green region, as is the case in classical photothermorefractive glass. This makes it possible to record purely phase holograms in modified photothermorefractive glass. The refractive-index increment is a factor of 2 greater in modified photothermorefractive glass than in classical photothermorefractive glass.

The purpose of this work is the study of laser cleaning of historical paper. The effect of laser exposure of the paper reflectance, fracture resistance and acidity was investigated. The paper surface roughness before and after laser treatment was analyzed by optical and scanning electron microscopy. It was shown that use of multi-pulse micromachining in combination with high-speed scanning of laser beams provides high safety for paper cleaning. The optimal parameters of laser radiation for effective and safe cleaning are a power density of about 2 × 105 W/cm² at a wavelength of 1.06 μm, pulse repetition rate is 20 kHz; and a beam scanning speed of 200 mm/s–500 mm/s. The selective laser cleaning method for books and documents was proposed. Selective cleaning is achieved by means of high-precision control of the trajectory of movement of laser beams.

The study of the chemical composition of historical glasses is widely used in archaeometry. The results of such analyses provide information on the probable date, place, and technological features of their production. Over time, a weathered layer may form on the surface of the glass, which differs in composition from the original one. To determine the initial composition using conventional methods (for example, X-ray fluorescence spectroscopy), the weathered layer should be removed. For historical objects, such manipulation is unacceptable and should be minimized. One of the methods for analyzing the chemical composition with minimal damage to a sample is laser-induced breakdown spectroscopy. The aim of this work was to develop a LIBS method, which makes it possible to perform a quantitative analysis of lead silicate glasses, including glasses containing a weathered layer. Reference glasses with a variable content of potassium, silicon, and lead oxides were synthesized, and based on the LIBS spectra, a calibration dependence was obtained that made it possible to measure the concentration of lead and potassium oxides in glasses within 70–85 and 5–20 wt%, respectively. The method was applied to analyze the composition of the glaze on a historic glazed tile from the burial church in the Euphrosinian monastery in Polotsk (the second half of the 12th century AD). The crater formed with the laser beam on the glazed surface was about 200 microns. Such damage is negligible compared to the total surface area of the tile (~10 cm²). The thickness of the weathered glaze layer was 70 microns, which was determined using variation in lead oxide content.

A technology for production of nano-glass-ceramic materials based on aluminosilicate glass doped with chromium oxide is proposed. A comparative study of the spectral luminescence properties of forsterite glass ceramics and single crystal doped with chromium ions is performed. It is shown that chromium ions are partially incorporated into the glass-ceramics crystalline phase. The quantum luminescence yields of Cr⁴⁺ ions in forsterite nano glass ceramics and single crystal are found to be close.

Rare earth activated powders are widely regarded as promising candidates for optical thermometry due to their unique photoluminescence characteristics. The paper presents the structural and luminescent properties of crystalline powders of gadolinium and yttrium oxides (Gd_1−xY_x)₂O₃, doped with Nd³⁺ ions, synthesized by the liquid polymer-salt method. The addition of polyvinylpyrrolidone increases the homogeneity of the mixture and ensures high adhesion of the resulting powders. Scanning electron microscopy shows that powders are μm-sized aggregates, which consist of particles with several tens of nanometers in size. A smooth shift of the diffraction peaks of the powders occurs when Gd is replaced by Y without additional peaks. The successive decrease in the lattice constant of the powders from 10.816 to 10.607 Å confirms the existence of continuous solid solutions in the system. The Stark sublevels of the ⁴F_3/2 → ⁴I_9/2 fluorescent band are shifted to 4 nm when Gd is replaced by Y since the strength of the local field has a stronger effect on the inner F-shell of Nd ions in the case of Y. For thermometry, we chose the ratio of the fluorescence intensities between the Stark sublevels ⁴F_3/2(2) → ⁴I_9/2(2) and ⁴F_3/2(1) → ⁴I_9/2(2). The best obtained sensitivity is 0.22% °C⁻¹ for Nd-doped GdYO₃ powder in the range of 10–70 °C. This value of temperature sensitivity, together with radiation and excitation lying in the biological window, opens the possibility of using Nd³⁺-doped (Gd_1−xY_x)₂O₃ powders for real-time thermal probing of under tissue luminescence with sub-degree resolution.