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VIS emission spectra of SZC-xBi0.6Eu2Yb (x = 1.0, 1.2, 1.4, 1.6, and 1.8 mol%) zinc calcium silicate glass samples under 320 nm excitation.

In this study, lanthanum aluminosilicate glasses with compositions of 45SiO2–20Al2O3–12.5LaF3–10BaF2–9K2O–1Cr2O3–2.5Yb2O3 (SALBK) were prepared using the conventional melting method and copper–potassium ion exchange process. Influences of the ion exchange process between copper and potassium on the visible, upconversion, and near-infrared luminescence spectra of Cr3+/Yb3+ co-doped under excitations of 343, 490, and 980 nm LD were investigated. The EDS analysis of SALBK glasses was measured to confirm the presence of atoms in the glasses. The values of direct and indirect bandgaps of Cr3+/Yb3+ co-doped SALBK glasses were calculated and analyzed. Besides, the energy exchange processes between Cu+, Cu2+ ions, and Cr3+, Yb3+ ions were also proposed and discussed.

Super broadband NIR (near-infrared) emission and energy transfer of Nd–Bi–Er co-doped transparent silicate glass-ceramics under excitation 808 nm laser diode were investigated. Super broadband NIR emission in Nd–Bi–Er co-doped extending from 1000 to 1600 nm with a full-width at half-maximum (FWHM) of 600 nm were observed. This result is due to the overlapping NIR emission band centered at 1275 nm (ES1 → GS) of Bi-related and NIR emission band centered at 1063 nm (4F3/2 → 4I11/2) of Nd3+ as well as NIR emission spectral band centered at 1546 nm (4I13/2 → 4I15/2) of Er3+. At the same time, the energy transfer processes between Bi-related, Nd3+ and Er3+ were also discussed and proposed.

The near/mid-infrared emission of Er3+-doped, Er3+-Yb3+ co-doped and Er3+-Mn2+-Yb3+ tri-doped in 40SiO2–(22.9-x)Al2O3–20BaF2–10LaF3–5TiO2– xMnO–0.1Er2O3–2Yb2O3 (in mol.%, x = 0, 2.0, 4.0, 6.0 and 10.0) (acronym: SGC-xMn) transparent silicate glass-ceramics were prepared. Enhanced near/mid-infrared emission intensity of Er3+-doped bands centered at ∼1.54 and ∼2.73 µm in transparent silicate glass-ceramics via Mn2+–Yb3+ dimer under 980 nm excitation were investigated. XRD results indicate that the Mn2+ ions are dispersed into the glass matrix. With the forming of Mn2+–Yb3+ dimer and the energy transfer processes from Mn2+–Yb3+ dimer and Mn2+ to Er3+ ions has led to NIR emission intensity of Er3+-doped at ∼1.54 µm was increased significantly about four-fold and the MIR emission intensity of Er3+-doped at ∼2.73 µm was increased about third-fold. In addition, based on the decay time spectra, mechanism of energy transfer processes between Mn2+–Yb3+ dimer, Mn2+ and Er3+ ions were also discussed.

In this study, lanthanum aluminosilicate glasses with compositions of 45SiO

The Bi+-doped, Nd3+-doped, and Nd3+-Bi+ co-doped in SiO2–Al2O3–BaF2–LaF3–TiO2 transparent silicate glass-ceramics were fabricated by conventional melting-quenching technique. The super broadband near-infrared luminescence, decay time spectra in Nd3+-Bi+ co-doped transparent silicate glass-ceramics under 808 nm excitation were investigated. The interesting in this paper is due to energy transfer between Bi+ and Nd3+ ions already exists lead to super broadband NIR emission extending from 1050 to 1550 nm with a full-width at half-maximum (FWHM) of 480 nm which covered the whole O, E and S bands were observed in the Nd3+-Bi+ co-doped transparent silicate glass ceramics. In addition, based on the decay time spectra, mechanism of energy transfer processes between Bi+ and Nd3+ ions were also discussed and proposed.

The SiO2-Al2O3-BaF2-TiO2-CaF2 transparent silicate glass-ceramics containing BaF2 nanocrystals were successfully prepared by heat treatment process through conventional melting method. Effects of heat treatment processes and Yb3+ concentration on the downconversion (DC) emission of the co-doped Er3+/Yb3+ transparent silicate glass-ceramics were investigated. With the increase of temperatures and times of heat treatment process, the DC emission intensity of the co-doped Er3+/Yb3+ glass-ceramics was significantly enhanced. At the same time, with the increase of Yb3+ concentration, the value of DC intensity of Er3+/Yb3+ co-doped bands centered at 849, 883 and 1533 nm is maximized when the concentration of Yb3+ reaches 2.5 mol.%. When the concentration exceed 2.5 mol. %, the DC emission intensity of Er3+/Yb3+ co-doped bands centered at 849, 883 and 1533 nm was decreased, owing to the self-quenching effect. It’s interesting that the DC emission intensity of Er3+/Yb3+ co-doped band centered at 978 nm didn’t quench when the Yb3+ concentration exceed 2.5 mol. %. At the same time, the DC mechanism and ET processes between Yb3+ and Er3+ ions were discussed.

We investigate and report the broadband flat near-infrared (NIR)/mid-infrared (MIR) emissions of Tm3+–Ho3+ co-doped, and Tm3+–Ho3+–Yb3+ tri-doped SiO2–ZnO–K2O–La2O3 zinc silicate glasses under excitation of 808 and 980 nm laser diode (LD). Broadband relatively flat MIR emissions of Tm3+–Ho3+ co-doped, and Tm3+–Ho3+–Yb3+ tri-doped with a full-width at half-maximum (FWHM) of about 420, and 390 nm corresponding to commercial of 808, 980 nm LD excitations were identified. The role of Yb3+ in enhancing the intensity of the NIR/MIR emissions of Tm3+–Ho3+ co-doped, and Tm3+–Ho3+–Yb3+ tri-doped was also investigated. The GTm(λ), GHoλ) gain coefficient spectra of Tm3+ single-doped, and Ho3+ single-doped were determined respectively. Besides, the mechanisms for cross-relaxation (CR), energy transfer (ET), cooperative ET (CET) processes between Tm3+, Ho3+, and Yb3+ are proposed and discussed.

The effects of Mn 2+ ions on the enhancement red upconversion emission intensity of Mn 2+ /Tm 3+ /Yb 3+ tri-doped transparent glass-ceramics were investigated. The ratio I 698nm / I 478nm significantly increases about ten-fold with the increase of Mn 2+ concentrations up to 4.0 mol.%. The red upconversion emission of Mn 2+ /Tm 3+ /Yb 3+ tri-doped transparent glass-ceramics is greatly enhanced, due to constitution of the energy transfer bridge. The upconversion mechanism, the energy transfer and back energy transfer processes between the ( 1 G 4 → 3 H 6 ), ( 3 F 2 → 3 H 6 ) transitions of Tm 3+ ions and the ∣ 2 F 7/2 , 4 T 1 〉 → ∣ 2 F 7/2 , 6 A 1 〉 transitions of Mn 2+ –Yb 3+ dimer were discussed.

In this article, using the operator projection technique, we will theoretically study the electron-interface phonon scattering process due to the absorbtion and emission of interface phonons by calculating the expression for the absorption power (AP) in GaAs/AlAs quantum wells (QWs). The full width at half maximum (FWHM) of the magneto-interface phonon resonance peaks was obtained by using the profile method. The FWHM is given as functions of the temperature, well width, and magnetic field presented to compare for both the barrier material AlAs and well material GaAs in the two cases of emission and absorbtion of interface modes. The result clearly demonstrates important roles of the interface optical modes when the well width is small enough.

In this paper, the upconversion (UC) emission of Tm3+/Cr3+/Yb3+ tri-doped in SiO2–AlF3–BaF2–La2O3 transparent fluorosilicate glass-ceramics (SGC) containing Ba2LaF7 nanocrystals were investigated. The enhancement of red UC emission of Tm3+/Cr3+/Yb3+ tri-doped in SiO2–AlF3–BaF2–La2O3 transparent SGC were also investigated. Through the energy transfer processes between Cr3+ and Tm3+, and the combination of Cr3+-Tm3+ led to the red UC emission intensity of Tm3+/Cr3+/Yb3+ tri-doped transparent SGC bands centered at ~806 and ~858 nm has been significantly enhanced. The CIE chromaticity coordinates for UC emission of Tm3+/Cr3+/Yb3+ tri-doped in SGC-0.2Tm1Cr2Yb transparent SGC sample is calculated (x = 0.704; y = 0.296) and the UC emission of Tm3+/Cr3+/Yb3+ tri-doped in SiO2–AlF3–BaF2–La2O3 transparent SGC has been identified in red color region of CIE chromaticity coordinates. In addition, the ET processes between Cr3+ and Tm3+ are also proposed and discussed.

We study effects of Y3+ on the enhancement near-infrared emission of Bi+-Er3+ co-doped in transparent silicate glass-ceramics for optical amplifiers. The differential thermal analysis, X-ray diffraction, transmission electron microscopy to determine the effects of Y3+ on the structure of BaF2 nanocrystals in glass-ceramics. With increasing the concentration of Y3+ from 0 up to 10 mol. %, the near-infrared emission intensities of Bi+-doped, Er3+-doped and Bi+-Er3+ co-doped bands centered at 1276 and 1546 nm also increase, and the full width at half maximum is about 460 nm. At the same time, when the concentration of YF3 increases from 4 up to 10 mol. %: all the glass transition temperature, the crystallization onset temperature, and the crystallization peaks temperature increase, resulting in a shift of the 2θ with a difference Δθ = 0.3°. In addition, we study the thermal properties through differential thermal analysis curves.

In this paper, the upconversion/downconversion (UC/DC), visible (VIS) and near-infrared (NIR) emissions of Cr3+/Yb3+ co-doped TeO2–ZnO–La2O3 (TZL) tellurite glasses under different wavelength excitation lights were investigated. The CIE 1931 chromaticity coordinates for UC emission of Cr3+/Yb3+ co-doped TZL tellurite glasses under different excitation wavelengths were also investigated. Through the energy transfer (ET) and cooperative energy transfer (CET) processes from Cr3+ to Yb3+ and the combination of Cr3+-Yb3+ lead to the intensity of UC-, DC-, VIS-, NIR-emissions of Cr3+/Yb3+ co-doped TZL tellurite glasses significantly increased. Under different wavelength excitation lights, the optimal concentration of Yb3+ for the UC-, DC-, and VIS- emissions of Cr3+/Yb3+ co-doped TZL tellurite glasses is different. In addition, the ET, CET processes between Cr3+ and Yb3+ are also proposed and discussed.

The Bi-doped in 55SiO2–xAl2O3–(40–x) La2O3–5TiO2–1Bi2O3 (x = 10, 15, 20, 25, 30, 32 and 35) lanthanum aluminosilicate glasses were fabricated by conventional melting-quenching technique. Effects of Al3+/La3+ ratio on the Differential scanning calorimetry/Differential thermal analysis (DSC/DTA) and luminescence properties of Bi-doped in SiO2–Al2O3–La2O3–TiO2 lanthanum aluminosilicate glasses was investigated. The Fourier transform infrared (FTIR) spectroscopy has also been investigated for structural analysis of the glasses. Near-infrared (NIR) emissions spectra of Bi-doped peaks exist at ~1120 and 1275 nm have originated from Bi0 and Bi+ ions, respectively, with the full-width at half-maximum (FWHM) lager than 250 nm was strongly observed. The visible luminescence of Bi-doped bands centered at ~430 and 660 nm arises from Bi3+ and Bi+ ions respectively were also observed. The emissions intensity of Bi-doped bands centered at ~660, 1120 and 1275 nm were significantly increased with the increasing of Al3+/La3+ ratio from 1:3 up to 3:1 ratio. Simultaneously, the visible emission intensity of Bi-doped band centered at 430 nm was decreased with the increasing of Al2O3 concentration.

The optimizing Nd/Er ratio for enhancement of broadband near-infrared (NIR) emissions in the Er 3 + –Nd 3 + co-doped SiO 2 –AlF 3 –BaF 2 –TiO 2 –CaCO 3 (SABTC) transparent silicate glass-ceramics containing BaF 2 nanocrystals under 808 nm excitation was investigated. The broadband NIR emission bands from 850 to 1700 nm, which covered the whole O, E, S, C, L and U bands were observed in the Er 3 + –Nd 3 + co-doped glass-ceramics samples, as a result of the overlap of Nd 3 + -doped emission band centered at 1342 nm and the emission from 4 I 13/2 → 4 I 15/2 transition of Er 3 + band centered at 1546 nm. The NIR emission intensity of Er 3 + –Nd 3 + co-doped bands centered at 895, 1065, 1342 and 1546 nm, becomes stronger with varied depending on the mixing ratio of Nd 3 + and Er 3 + ions, and the full width at half-maximum (FWHM) extending from 1250 to 1700 nm could be 340 nm. Most NIR emission bands at 1065 and 1546 nm are observed for the SABTC-1.0N0.4E glass-ceramics sample, corresponding to Nd/Er ratio of 2.5. At the same time, the energy transfer processes between the Nd 3 + and Er 3 + ions were also discussed.

The transparent glass–ceramics SiO 2 –AlF 3 –BaF 2 –TiO 2 –CaCO 3 containing BaF 2 nanocrystals were successfully prepared by the conventional melting method. The effect of the AuNPs on the enhancement upconversion and near-infrared emission in Er 3+ /Yb 3+ co-doped transparent glass–ceramics under 980 nm laser diode excitation were investigated. The transmission electron microscopy (TEM) micrograph showed the average diameter size of gold nanoparticles is estimated about 4–6 nm. Compared with the glass–ceramics sample without HAuCl 4 , the upconversion and near-infrared emissions intensity of SAB glass–ceramics samples with HAuCl 4 were significantly increased. Particularly, the red UC emission intensity band centered at 850 nm strongly increased about twenty-fold with the increase of HAuCl 4 concentration and reaches its maximum at 1.5 mol%, then decreases due to the self-quenching effect. The possible mechanism responsible for the enhancement of upconversion and near-infrared emission in Er 3+ /Yb 3+ co-doped due to effectiveness of surface plasmon resonance were discussed.

The glass and glass-ceramics samples with composition of 50SiO2–10AlF3–(30−x)BaF2–5TiO2–3.95LaF3– xMnCO3–0.05ErF3–1YbF3 (in mol%, x=0, 0.5, 0.8, 1.0, and 1.2) were prepared using the conventional quenching techniques. The effects of Mn2+ ions on the enhancement red upconversion emission of Mn2+/Er3+/Yb3+ tri-doped transparent glass-ceramics under the changing of heat treatment temperatures and concentrations of Mn2+ ions were investigated. The structural investigation carried out by X-ray diffraction (XRD), and transmission electron microscopy evidenced the formation of cubic Ba2LaF7 nanocrystals. The efficiency upconversion emission of Mn2+/Er3+/Yb3+ tri-doped was observed in the glass-ceramics. The upconversion mechanism and energy transfer between Mn2+–Yb3+ dimer and Er3+ ions were investigated.

Transparent glass-ceramics SiO2–AlF3–BaF2–TiO2–LaF3 (SABTL) containing Ba2LaF7 nanocrystals were successfully prepared by heat treatment process through conventional melting method. The crystal size in the glass-ceramics increased gradually under the changing of heat treatment temperatures and times, which was confirmed by the results of XRD, TEM measurements. The intensity of the blue, green and red upconversion luminescence around 490 nm, 525 nm, 546 nm, 657 nm which originate from the transitions 5D4 → 7FJ (J = 6 and 5) of Tb3+ ions and (2H11/2, 4S3/2, 4F9/2) → 4I15/2 transitions of Er3+ ions, respectively, were strongly observed after heat treatment under 980 nm laser diode excitation. The intensity of upconversion luminescence was increased gradually with the increase of Yb3+ concentrations and reaches its maximum at 2.5 mol%. The upconversion luminescence and energy transfer process between Tb3+, Yb3+ and Er3+ ions in the glass-ceramics were discussed.

TeO2–ZnO–Na2CO3–La2O3 (TZNL) tellurite glasses were prepared using a conventional melt-quenching method. The effects of the Mn2+ ions and (Yb3+–Mn2+–Mn2+) trimer on the enhancement upconversion (UC) and near-infrared (NIR) emissions intensity of the co-doped Ho3+/Yb3+ bands in TZNL tellurite glasses were investigated. With the formation of the (Yb3+–Mn2+–Mn2+) trimer and the energy transfer (ET) from Mn2+ and (Yb3+–Mn2+–Mn2+) trimer into Ho3+, the UC/NIR emissions intensity of the co-doped Ho3+/Yb3+ bands was significantly increased. In addition, the ET processes between the Mn2+ and (Yb3+–Mn2+–Mn2+) trimer with Ho3+ were shown.

Near-infrared (NIR) quantum cutting (QC) and upconversion (UC) emission of Nd3+–Yb3+ co-doped in Si–Al–Ba–La transparent silicate glass-ceramics (SGC) were prepared. Influence of La3+ on the enhancement NIR QC and UC emission intensity of the co-doped Nd3+–Yb3+ in SGC were investigated. Thereby, NIR QC and UC emission intensity of the co-doped Nd3+–Yb3+ were increased strongly with increasing concentration of LaF3 from 5 up to 25 mol. %. The value of NIR QC emission intensity of the co-doped Nd3+–Yb3+ band centered at ~890, 947, 1071, 1339 and 1430 nm is maximized when the concentration of LaF3 reaches 25 mol. %. At the same time, with the increasing concentration of Yb3+, NIR QC emission intensity of the co-doped Nd3+–Yb3+ bands centered at ~890, 1071, 1339 and 1430 nm of Nd3+ and 947 nm of Yb3+ were gradually increased and reaches its maximum at 2.5 mol. % Yb3+, then decreased owing to the self-quenching effect. In addition, NIR QC mechanism and energy transfer (ET) processes between 2F5/2 → 2F7/2 transition of Yb3+ and transitions of Nd3+ are discussed.

The energy transfer and upconversion emission of Tm3 +/Tb3 +/Yb3 + co-doped transparent glass-ceramics 50SiO2–10AlF3–30BaF2–5TiO2–4LaF3 (SABTL) containing Ba2LaF7 nanocrystals under the changing of heat treatment temperatures and concentrations of Tm3 +/Tb3 +/Yb3 + ions were investigated. The structural investigation carried out by X-ray diffraction (XRD) and transmission electron microscopy evidenced the formation of cubic Ba2LaF7 nanocrystals. The efficiency upconversion emission of Tm3 +/Tb3 +/Yb3 + ions was observed in the glass-ceramics. The upconversion emission and energy transfer between Tm3 + and Tb3 + ions were investigated with the Yb3 + ions cooperatively upconversion emission, energy transfer between Tm3 + and Tb3 + ions.

The up-conversion of Er3+/Yb3+ co-doped transparent glass-ceramics 50SiO2-10AlF3-5TiO2-30BaF2-4LaF3-0.5ErF3-0.5YbF3 containing Ba2LaF7 nanocrystals under the changing of heat treatment temperature and time were investigated. The Ba2LaF7 nanocrystals precipitated from the glass matrix was confirmed by X-ray diffraction (XRD). The structural investigation carried out by XRD and transmission electron microscopy (TEM) evidenced the formation of cubic Ba2LaF7 nanocrystals with crystal size of about 14 nm. Comparing with the samples before heat treatment, the high efficiency up-conversion emission of Er3+/Yb3+ co-doped samples was observed in the glass-ceramics under 980 nm laser diode excitation. The increase in red emission intensity bands was stronger than the green bands when the crystal size increased. The mechanism for the up-conversion process in the glass-ceramics and the reasons for the increase of Er3+/Yb3+ co-doped up-conversion intensity after heat treatment were discussed.