Получены новые стекла системы TeO 2 –Na 6 P 6 O 18 . Методом дифференциальной сканирующей калориметрии изучено термическое поведение стекол в области 25–580°C, исследованы температурные зависимости теплоемкости в интервале 25–400°C. Определены характеристики расстеклования и стеклообразного состояния, подобраны аналитические зависимости температур стеклования и термодинамических характеристик стекол от их состава при t = 80°C. Проведен сравнительный анализ полученных зависимостей с аналогичными для изученных ранее бинарных систем на основе TeO 2 . Исследована оптическая прозрачность стекол в УФ-, видимой и ИК-областях спектра. Показана возможность введения в стекла оксидов редкоземельных элементов. Для стекла состава 0.89TeO 2 –0.08Na 6 P 6 O 18 –0.03Nd 2 O 3 изучены люминесцентные характеристики.

— New glasses in the TeO 2 –Na 6 P 6 O 18 system have been prepared, their thermal behavior has been studied by differential scanning calorimetry in the range 25–580°C, and their heat capacity has been determined as a function of temperature in the range 25–400°C. We have evaluated characteristics of the devitrification process and glassy state, obtained analytical representations of the glass transition temperature and the thermodynamic characteristics of the glasses as functions of their composition at 80°C, and carried out a comparative analysis of the results together with those for previously studied TeO 2 -based binary systems. Optical transmission of the glasses has been measured in the UV, visible, and IR spectral regions. We have demonstrated the possibility of doping the glasses with rare-earth oxides and studied luminescence properties of the glass with the composition 0.89TeO 2 –0.08Na 6 P 6 O 18 –0.03Nd 2 O 3 .

The conversion of infrared radiation of a Tm3+:YAP laser at a wavelength of 1.93 mu m into visible light in [(ZrF4)(0.4)-(BiF3)(0.6)](100-x)-(HoF3)(x) (x = 1.5 or 5 wt%) ceramic samples was investigated. The emission bands at wavelengths of 650 nm, 900 nm and 1100 nm corresponding to transitions from F-5(5), I-5(5) and I-5(6) levels to the ground state I-5(8) were observed in upconversion luminescence spectra. From the experimental data, an estimate of the crossrelaxation coefficient from S-5(2) was obtained. It was K-cr approximate to 1 x 10(-16) cm(3) s(-1). The threshold power density of Tm3+:YAP laser, at which a luminescence was observed on the ceramic samples, was about 0.85 W cm(-2).

In this study, a method is proposed to measure the spatial properties of laser emissions in the range of 2.0 mu m. The infrared emission spectrum is first converted into a spectrum in the visible range using a fluorozirconate ZBLAN:Ho3+ glass sample. Subsequently, the converted emission is detected using a Pulnix TM-7CN CCD camera and the laser beam image is numerically processed using a specialized software package in the Lab VIEW environment. This enables the measurement of intensity distribution over the beam cross-section of the diode-pumped CWYAP:Tm3+ laser emitting at 1.94 mu m. The beam quality factor, M-2 , is also evaluated. (C) 2020 Optical Society of America

It is suggested to use sodium hexametaphosphate as a new glass-forming agent for tellurite glasses. The limits of the glass-forming region were determined for the TeO 2 –(NaPO 3 ) 6 system, and a selective study of the thermal behavior of the glasses synthesized was carried out by the method differential scanning calorimetry. The optical transmission in the UV, visible, and IR spectral ranges was examined. It was shown that oxides of rare-earth elements can be introduced into the glass, which opens up prospects for application of the system as a matrix for generation of laser light in the 2-μm range, required in fabrication of medical lasers.

Показано преобразование ИК излучения Tm : YAP-лазера с длиной волны 1930 nm в видимый свет керамикой состава LiY (1-x-y) Hox , Yby , где x = 1-5 mol.% и y = 0-15 mol.%.Показано, что величина пороговой плотности мощности визуализации ИК излучения снижается при увеличении концентрации ионов Ho 3+ , а дополнительное легирование образцов керамики ионами Yb 3+ изменяет спектр антистоксовой люминесценции.Величина пороговой плотности мощности визуализации излучения Tm : YAP-лазера при увеличении содержания ионов гольмия снижалась и в

Visualization of IR radiation of a Tm:YLF laser with a wavelength of 1908 nm in 53ZrF4–20BaF2–3LaF3–1HoF3–3AlF3–20NaF (mol %) ceramic samples is studied. The luminescence spectra of Но3+-doped ZBLAN ceramics exhibit bands in the regions of 540, 650, and 900 nm, which correspond to the 5S2 → 5I8, 5F5 → 5I8, and 5I5 → 5I8 transitions, the red band (650 nm) being most intense. The population of the upper levels of these transitions can be explained using the cascade excitation mechanism. A visualization model is developed based on balance equations for populations of the upper energy states of Но3+ ions. The population distributions are numerically estimated as functions of the excitation intensity. The obtained time dependences of the populations of the 5S2 and 5F5 states correlate with the experimental time dependences of the luminescence intensity at the 5S2 → 5I8 and 5F5 → 5I8 transitions upon pulsed excitation. The threshold power density of a Tm:YLF laser at which luminescence of the ceramic samples was observed was ~2 W/cm2.

Исследована визуализация ИК излучения Tm : YLF-лазера на длине волны 1908 nm в образцах керамики 53ZrF 4 -20BaF 2 -3LaF 3 -1HoF 3 -3AlF 3 -20NaF (mol%).В спектрах люминесценции легированных Но 3+ ZBLAN-керамик наблюдались полосы в областях длин волн 540, 650 и 900 nm, соответствующих переходам 5 S 2 → 5 I 8 , 5 F5 → 5 I 8 , 5 I5 → 5 I 8 с максимальной интенсивностью красной полосы (650 nm).Заселение верхних уровней этих переходов может быть объяснено с помощью механизма каскадного возбуждения.На основе системы балансных уравнений для населенностей энергетических состояний ионов Но 3+ создана модель визуализатора.Сделаны численные оценки распределения населенностей в зависимости от интенсивности возбуждения.Полученные временные зависимости населенностей состояний 5 S 2 и 5 F5 коррелируют с экспериментальными зависимостями изменения интенсивности люминесценции на переходах 5 S 2 → 5 I 8 и 5 F5 → 5 I 8 при импульсном возбуждении.Пороговая плотность мощности излучения Tm : YLF-лазера, при которой на керамическом образце наблюдалось свечение, составила ∼ 2 W/cm 2 .

Conversion of IR radiation of a Tm:YAP laser with a wavelength of 1930 nm into visible light by ceramics of composition LiY (1– x–y) Ho x Yb y , where х = 1–5 mol % and y = 0–15 mol %, is demonstrated. It is shown that the threshold power density of IR light visualization decreases with increasing concentration of Ho 3+ ions, while additional doping of ceramic samples with Yb 3+ ions changes the anti-Stokes luminescence spectrum. The threshold power density of visualization of the Tm:YAP laser radiation decreases with increasing concentration of holmium ions and is I thr ≈ 0.8 W cm –2 in the samples of composition LiYF 4 :5%Ho 3+ –15%Yb 3+ .

We demonstrate the up-conversion of Tm:LiYF4 infrared (IR) laser radiation with 1908-nm wavelength into visible light with a spectral maximum at 650 nm by ceramics with a composition of (100 − x)TeO2−xBaF2 − 1 wt % HoF3−yYbF3, where x = 20, 30, or 40 mol % and y = 0 or 0.5 wt %. The samples of 60TeO2−40BaF2 − 1 wt % HoF3 − 0.5 wt % YbF3 exhibited anti-Stokes luminescence at a threshold radiation power density of 1.0−1.5 W cm−2.

We demonstrate the up-conversion of Tm:LiYF 4 infrared (IR) laser radiation with 1908-nm wavelength into visible light with a spectral maximum at 650 nm by ceramics with a composition of (100 − x )TeO 2 − x BaF 2 − 1 wt % HoF 3 − y YbF 3 , where x = 20, 30, or 40 mol % and y = 0 or 0.5 wt %. The samples of 60TeO 2 −40BaF 2 − 1 wt % HoF 3 − 0.5 wt % YbF 3 exhibited anti-Stokes luminescence at a threshold radiation power density of 1.0−1.5 W cm −2 .

Показано преобразование ИК-излучения лазера Tm : LiYF4 с длиной волны 1908 nm в видимый свет с максимумом 650 nm керамикой состава (100-x)TeO2-xBaF2-1 wt% HoF3-yYbF3, где x=20,30,40 mol.%, y=0 или 0.5 wt%. На образцах 60TeO2-40BaF2-1 wt% HoF3-0.5 wt% YbF3 наблюдалась антистоксовая люминесценция при пороговой плотности мощности излучения 1.0-1.5 W · cm-2. DOI: 10.21883/PJTF.2017.14.44829.16771

The thermal behavior of (TeO2) n (MoO3)1–n (n = 0.75, 0.85, 0.90) tellurite glasses has been studied by differential scanning calorimetry in the range from T = 300 to T = 850 K and heat capacity has been measured in the temperature range. The thermodynamic characteristics of the devitrification process and glassy state have been determined. The experimental data obtained have been used to evaluate the standard thermodynamic functions of the system in glassy and supercooled liquid states: heat capacity C p °(T), enthalpy H°(T)–H°(320), entropy S°(T)–S°(320), and Gibbs function G°(T)–G°(320) in the temperature range 320–630 K. The composition dependences of the glass transition temperature and thermodynamic functions for the glasses have been obtained. The thermal and thermodynamic properties of the tellurite glasses have been compared to those of previously studied (TeO2) n (WO3)1–n and (TeO2) n (ZnO)1–n glasses.

Visualization of infrared radiation of Tm:YLF-laser at the wavelength of 1908 nm has been investigated in the glass and ceramics samples with compositions of 53ZrF(4) center dot 20 BaF2 center dot 1HoF(3) center dot 3YbF(3) center dot 3AlF(3) center dot 20NaF and 53ZrF(4) center dot 20BaF(2) center dot 3LaF(3) center dot 1HoF(3) center dot 3AlF(3) center dot 20NaF (mol %). In luminescence spectra of ZBLAN samples doped with DeD3/4(3+), the bands at the wavelengths of 480, 540, and 650 nm were observed, which correspond to (5) F (3) -> (5) I (8), (5) S (2), (5) F (4) -> (5) I (8), and (5) F (5) -> (5) I (8) electron transitions in DeD3/4(3+) ions with the maximum intensity of the red band (650 nm). Occupancy of the (5) S (2) and (5) F (4) levels in the ZBLAN: 1% DeD3/4(3+) samples is related to the sequential absorption of the exciting radiation quanta. The level of (5) F (5) is filled mainly due to the ionic interaction. Additional doping with the Yb3+ ions led to the change of the luminescence color to green and a decrease in the threshold radiation power density of the Tm:YLF-laser in ceramic samples up to 2 W/cm(2).

Visualization of IR radiation of a Tm:YLF laser at 1908 nm in PbF2 ceramic samples has been investigated. Luminescence spectra of the PbF2 samples doped with Нo3+ exhibited bands at wavelengths of 490, 545, and 650 nm (this red band is the strongest). It is established that at, a low laser intensity, the 5I5 and 5I6 levels are occupied mainly due to the ion–ion energy transfer.

Ho3+-doped bismuth(III) fluoride was suggested for upconversion of 2-μm laser radiation (1.9–2.1 µm) into visible emission. The process is possible owing to direct excitation of the 5I7 level, followed by the excitation of the 5F5 level with the emission threshold of 1.4 W.

A ceramic 2-µm laser beam visualizer based on Ho3+-doped β-BaZrF6 is proposed. The ceramic has been prepared by crystallizing 60ZrF4–35BaF2–5BiF3 glass doped with 3 wt % HoF3. Exciting the Ho3+5 I 7 level by a Tm:LiYF4 (Tm:YLF) laser at λ = 1910 nm, we observed a strong red luminescence, due to the 5 F 5 → 5 I 8 transition, and a weaker, green luminescence, corresponding to the (5 F 4, 5 S 2) → 5 I 8 transition. The threshold power density of the Tm:YLF laser at which a red spot was observed on a ceramic sample was 1.1 W/cm2.