arXiv subjects

Mykhailo Chaika

Publications and source records attributed to Mykhailo Chaika.

4 recordsLinked to original sources

arXiv2026

Introduction to Spectroscopy of Cr4+:YAG Transparent Ceramics

This paper focuses on the spectroscopic properties of Cr4+:YAG transparent ceramic. Absorption, excitation, and emission spectra were measured over a temperature range from 5K to 300K. Low-temperature absorption spectra reveal sharp and narrow lines corresponding to partially allowed transitions from the ground state to the crystal field splitting components of the 4T2 energy level. The shape of the excitation spectra was found to be independent of the monitored emission wavelength, indicating that Cr4+ emission originates from the lowest excited state. Low temperature emission spectra exhibit a sharp and narrow ZPL, accompanied by the vibronic sidebands extending up to ~2000 cm-1. Both absorption and emission spectra of the lowest excited state at low temperature consist of a doublet, with a splitting of 28 cm-1. The temperature dependence of the spectroscopic parameters of this doublet is reported. Based on the obtained results, possible explanations of its origin are proposed.

cond-mat.mtrl-sci↗

arXiv2025

Toward more performant eye safe lasers: effect of increasing sensitizer amount in Yb3+,Er3+:YAG transparent ceramic on its spectral characteristics

Developing efficient Er3+,Yb3+:YAG eye-safe lasers is a priority of modern laser technology. This paper focuses on the influence of the concentration of Yb3+ ions on the spectroscopic properties of Er3+,Yb3+:YAG transparent ceramics. Four samples with different concentrations of Yb3+ ions were prepared by solid-state reaction sintering. The study revealed the influence of Yb3+ ions on the microstructure and the sintering process. A high concentration of Yb3+ ions leads to the formation of Y3+-rich impurity phases and causes segregation of Er3+ and Yb3+ and Si4+ into these phases. The influence of Yb3+ ions on the shape of emission spectra and the lifetimes of both Er3+ and Yb3+ ions was shown. Changes in the spectroscopic properties were ascribed to increase in neat transfer between Yb3+ and Er3+ ions. IQE of Er3+ and Yb3+ luminescence were calculated, and optimal Er3+/Yb3+ ions ratio were proposed

cond-mat.mtrl-sci↗

arXiv2025

Temperature-Dependent Spectroscopy of Cr3+:YGG Nanophosphors with Multisite Emission

An important feature of Cr3+ is the ability to tune the absorption and emission spectra by changing the host. However, in some cases, different emission spectra can be detected in samples with similar Racah parameters. The present paper reports changes in the luminescence properties of Cr3+:YGG nanocrystals. Cr3+:YGG nanocrystals were synthesized by a modified Pechini method to obtain nanocrystals containing two fractions of Cr3+:YGG nanocrystals with different lattice parameters and crystalline sizes. The increase in the concentration of Cr3+ ions leads to a redshift of the 4T2g emission from 750 nm to 850 nm for luminescence spectra measured at 80K. In contrast, room temperature luminescence spectra showed similarity in the shape of the emission spectra. The calculated crystal field strength was found to increase with the concentration of Cr3+ ions, so the detected patterns in low-temperature luminescence spectra were explained by energy transfer chain processes.

cond-mat.mtrl-sci↗

arXiv2025

Advancements and Challenges in Sintering Cr4+:YAG Ceramics: A Comprehensive Review on Transparent Ceramic Technology for Q-switched Lasers

The resent progress in the technology of transparent ceramics extends the application of CW and pulsed lasers. The parameters of the transparent ceramics are comparable with the single crystals both for active elements (Nd:YAG, Yb:YAG, etc.) and passive Q-switchers such as Cr4+:YAG. Despite the reaching of considerable progress, the sintering of Cr4+:YAG remains a challenge up to now. Up to the present the influence of the CaO, MgO and Cr2O3 additives on the sintering process is poorly understander. Moreover, there is an absence of the unified model of Cr4+ ions formations in YAG ceramics. This factor limits the progress in the development of Cr4+:YAG ceramics. This review focused on the influence of the single additives and their combinations on the sintering trajectory of tetravalent chromium - doped YAG ceramics and the Cr4+ ions formation.

cond-mat.mtrl-sci↗