Stokes Emissions Research Articles

Observing high dependence of red luminescence on localized symmetry in Mn4+ activated inverse spinel phosphors.

Localized symmetry has been shown to significantly impact the luminescence behavior of Mn4+ ions through the electron-phonon coupling process. Building on this characteristic, three types of inverse spinel structure oxides (Mg2XO4, where X = Ti, Ti/Ge, Ge) doped with Mn4+ were developed, exhibiting strong red emission when exposed to UV and blue light. A thorough examination reveals that the symmetric improvement of the Mn4+ sites within the octahedral environment leads to significant changes in their luminescence behavior, including a suppression of zero-phonon-line (ZPL) emission, a blueshift, and an extension of the luminescence lifetime. Moreover, variable-temperature PL spectra of phosphors are carefully measured. Low-temperature PL spectra demonstrate three distinct sharp emission peaks for Mg2GeO4:Mn4+, while Mg2TiO4:Mn4+ exhibits a broad emission band. The average primary phonon energies involved in the vibronic processes are determined through theoretical fitting of temperature-dependent PL intensities. Lastly, the luminescence dynamics associated with anti-Stokes, ZPL, and Stokes emissions are analyzed. The observed increase in luminescence lifetime indicates a significant impact of the localized environment on luminescence properties.

Modulating the Luminescence, Photosensitizing Properties, and Mitochondria-Targeting Ability of D-π-A-Structured Dihydrodibenzo[a,c]phenazines.

Herein, pyridinium and 4-vinylpyridinium groups are introduced into the VIE-active N,N'-disubstituted-dihydrodibenzo[a,c]phenazines (DPAC) framework to afford a series of D-π-A-structured dihydrodibenzo[a,c]phenazines in consideration of the aggregation-benefited performance of the DPAC module and the potential mitochondria-targeting capability of the resultant pyridinium-decorated DPACs (DPAC-PyPF6 and DPAC-D-PyPF6). To modulate the properties and elucidate the structure-property relationship, the corresponding pyridinyl/4-vinylpyridinyl-substituted DPACs, i.e., DPAC-Py and DPAC-D-Py, are designed and studied as controls. It is found that the strong intramolecular charge transfer (ICT) effect enables the effective separation of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of DPAC-PyPF6 and DPAC-D-PyPF6, which is conducive to the generation of ROS. By adjusting the electron-accepting group and the π-bridge, the excitation, absorption, luminescence, photosensitizing properties as well as the mitochondria-targeting ability can be finely tuned. Both DPAC-PyPF6 and DPAC-D-PyPF6 display large Stokes shifts (70-222 nm), solvent-dependent absorptions and emissions, aggregation-induced emission (AIE), red fluorescence in the aggregated state (λem = 600-650 nm), aggregation-promoted photosensitizing ability with the relative singlet-oxygen quantum yields higher than 1.10, and a mitochondria-targeting ability with the Pearson coefficients larger than 0.85. DPAC-D-PyPF6 shows absorption maximum at a longer wavelength, slightly redder fluorescence and better photosensitivity as compared to DPAC-PyPF6, which consequently leads to the higher photocytotoxicity under the irradiation of white light as a result of the larger π-conjugation.

Multifunctional Platform Based on a Copper(I) Complex and NaYF4:Tm3+,Yb3+ Upconverting Nanoparticles Immobilized into a Polystyrene Matrix: Downshifting and Upconversion Oxygen Sensing.

This work presents an innovative approach to obtain a multifunctional hybrid material operating via combined anti-Stokes (upconversion) and Stokes (downshifting) emissions for oxygen gas sensing and related functionalities. The material is based on a Cu(I) complex exhibiting thermally activated delayed fluorescence emission (TADF) and infrared-to-visible upconverting Tm3+/Yb3+-doped NaYF4 nanoparticles supported in a polystyrene (PS) matrix. Excitation of the hybrid material at 980 nm leads to efficient transfer of Tm3+ emission in the ultraviolet/blue region to the Cu(I) complex and consequently intense green emission (560 nm) of the latter. Additionally, the green emission of the complex can also be directly generated with excitation at 360 nm. Independently of the excitation wavelength, the emission intensity is efficiently suppressed by the presence of molecular oxygen and the quenching rate is properly characterized by the Stern-Volmer plots. The results indicate that the biocompatible hybrid material can be applied as an efficient O2 sensor operating via near-infrared or ultraviolet excitation, unlike most optical oxygen sensors currently available which only work in downshifting mode.

Effect of Dimensionality on Photoluminescence and Dielectric Properties of Imidazolium Lead Bromides.

Hybrid organic–inorganic lead halide perovskites have emerged as promising materials for various applications, including solar cells, light-emitting devices, dielectrics, and optical switches. In this work, we report the synthesis, crystal structures, and linear and nonlinear optical as well as dielectric properties of three imidazolium lead bromides, IMPbBr3, IM2PbBr4, and IM3PbBr5 (IM+ = imidazolium). We show that these compounds exhibit three distinct structure types. IMPbBr3 crystallizes in the 4H-hexagonal perovskite structure with face- and corner-shared PbBr6 octahedra (space group P63/mmc at 295 K), IM2PbBr4 adopts a one-dimensional (1D) double-chain structure with edge-shared octahedra (space group P1̅ at 295 K), while IM3PbBr5 crystallizes in the 1D single-chain structure with corner-shared PbBr6 octahedra (space group P1̅ at 295 K). All compounds exhibit two structural phase transitions, and the lowest temperature phases of IMPbBr3 and IM3PbBr5 are noncentrosymmetric (space groups Pna21 at 190 K and P1 at 100 K, respectively), as confirmed by measurements of second-harmonic generation (SHG) activity. X-ray diffraction and thermal and Raman studies demonstrate that the phase transitions feature an order–disorder mechanism. The only exception is the isostructural P1̅ to P1̅ phase transition at 141 K in IM2PbBr4, which is of a displacive type. Dielectric studies reveal that IMPbBr3 is a switchable dielectric material, whereas IM3PbBr5 is an improper ferroelectric. All compounds exhibit broadband, highly shifted Stokes emissions. Features of these emissions, i.e., band gap and excitonic absorption, are discussed in relation to the different structures of each composition.

Third-order cascaded Raman shift in all-solid fluorotellurite fiber pumped at 1550 nm.

In this Letter, we demonstrate a third-order cascaded Raman shift in an all-solid fluorotellurite fiber pumped by a 1550 nm nanosecond laser. The fluorotellurite glass with a composition of TeO2-BaF2-Y2O3 (TBY) has a usable Raman shift of ∼785 cm-1 and a Raman gain coefficient of ∼1.65 × 10-12 m/W at 1550 nm, which is approximately 25.4 times larger than that of silica glass. By using a 5.38 m fluorotellurite fiber as the Raman gain medium and a 1550 nm nanosecond laser as the pump light, a third-order cascaded Raman shift is obtained via spontaneous cascaded Raman amplification in the fluorotellurite fiber, causing the generation of the first-, second-, and third-order Stokes emissions that peak at 1765, 2049, and 2438 nm, respectively. For an average pump power of ∼491.5 mW, the output power of the generated first-, second-, and third-order Stokes light is approximately 14.1, 67.4, and 31.6 mW, respectively. The corresponding conversion efficiency is approximately 2.87%, 13.70%, and 6.43%, respectively. Our results show that fluorotellurite fibers are promising Raman gain media for constructing cascaded Raman fiber lasers with a wide range of wavelengths.

Enhanced dual mode luminescence via energy transfer in Er3+, Yb3+ co-doped β-spodumene

Fundamental understanding of the Stokes and anti-Stokes emissions in luminescence materials and their mechanism is very important for different technological applications. In this article, we report the dual mode, down/upconversion (DC/UC), luminescence in a LiAlSi2O6 (β-spodumene) single host along with its mechanistic investigations. A series of emission tunable Li1-xAlSi2O6:xEr3+ (LAS:xEr3+; 0 ≤ x ≤ 0.07) and Li0.99-yAlSi2O6:0.01Er3+,yYb3+ (LAS:0.01Er3+,yYb3+; 0.001 ≤ y ≤ 0.007) phosphor powders were prepared by solid state reaction method at 1300 °C. The formation of single-phase phosphors is verified by XRD technique and other structural properties are investigated by FT-IR, UV-Vis-NIR spectra. The phosphors produced NIR DC emission at 1535 nm (under 380 and 980 nm excitation) and an intense red UC emission at 655 nm (under both 980 and 808 nm excitations). The dual mode emission intensity of the LAS:0.01Er3+ is further improved by co-doping Yb3+ ions via energy transfer from Yb3+ to Er3+. The red UC emission intensity of LAS:0.01Er3+,0.005Yb3+ phosphor under 980 nm excitation is ~10 times stronger than the singly doped LAS:0.01Er3+ phosphor. In addition, the phosphors can also be efficiently excited by 808 nm laser and hence can be used for biological application since 808 nm NIR irradiation exhibits higher light penetration depth without inducing overheating. The mechanism of energy transfer from Yb3+ to Er3+ by considering different emission pathways viz: ground state absorption (GSA), excited state absorption (ESA), energy transfer upconversion (ETU), back energy transfer (BET) and cross relaxation (CR) are discussed in detail. Based on the dual mode emissions, the LAS:xEr3+ and LAS: xEr3+,yYb3+ (x = 0.1 and 0.001 ≤ y ≤ 0.007) phosphors could be a potential candidate not only for the biological application as bio-probe but also as energy convertors for solid-state lighting, displays, and solar cell applications.

High-peak-power narrowband eye-safe intracavity Raman laser.

We demonstrated a narrowband eye-safe intracavity Raman laser by incorporating a fused silica etalon into the fundamental resonator. The KGd(WO4)2 (KGW) Raman laser was pumped by an actively Q-switched Nd:YLF laser at 1314 nm. Thanks to the KGW bi-axial properties, two distinct eye-safe Raman lasers operating at 1461 and 1490 nm were obtained separately by rotation of the KGW crystal. At an optimized pulse repetition frequency of 4 kHz, the maximum average output powers of 3.6 and 4.0 W were achieved with the peak powers up to approximately 330 and 480 kW, respectively. The eye-safe Stokes emissions were narrow linewidth (∼0.05 nm FWHM; measurement limited) and near diffraction limited (M2 < 1.4). The powerful narrowband eye-safe Raman lasers are of interest for applications as diverse as laser range finding, scanning lidar and remote sensing.

Dual-mode luminescent core-shell nanoarchitectures for highly sensitive optical nanothermometry

Currently, FIR-based luminescent nanothermometry has aroused wide concern for its promising applications in fast-moving objects, harsh environments and microscopic temperature. Synchronously promoting the absolute and relative sensitivities of optical thermometers is one of the significant issues at present. In this work, a new nanothermometry strategy to possess both high absolute and relative sensitivities have been proposed by coupling of thermally-coupled-levels-based technique with non-thermally-coupled-levels method in the core-shell designed nanomaterials. Following this strategy, the core-shell-structured NaGdF4:Yb,Er@ NaYF4:Ce,Tb,Eu nanocrystals have been successfully prepared. Remarkably, the adverse cross-relaxation among different activators is extremely suppressed owing to the spatial separation of Er3+ and Eu3+,Tb3+ activators, being conducive to the realization of both intense green upconverting emissions and yellow downshifting luminescence. Moreover, the temperature-sensitive dual-mode luminescent behaviors of core-shell nanomaterials are systematically studied to probe the possible application in FIR-related luminescent thermometry. Specially, the thermally-coupled-levels-based FIR of Er3+:2H11/2 → 4I15/2 transition to Er3+: 4S3/2 → 4I15/2 one and non-thermally-coupled-levels-based FIR of Eu3+:5D0→7F2 transition to Tb3+:5D4→7F6 one are proved to be applicable as temperature probes, leading to the achievement of dual-mode temperature sensing. Using the pre-designed core@shell nanoarchitectures, the absolute sensitivity can reach up to 1.02% K−1 based on Eu3+,Tb3+ Stokes emissions and the relative sensitivity could reach as high as 1.12% K−1 based on Er3+ anti-Stokes luminescence. We believe that this study provides a valid approach for developing high-performance optical nanothermometers.

Controlling Selective Doping and Energy Transfer between Transition Metal and Rare Earth Ions in Nanostructured Glassy Solids

AbstractSelective doping of optically active ions into the nanocrystalline phase(s) of glass ceramics is of interest for photoluminescence (PL) applications to control the energy transfer (ET) processes between dopants on the nanometer length scale. Here, the focus is on explaining the essential knowledge of the distribution of two groups of active ions: transition metal (Ni2+ and Cr3+) and rare earth (Yb3+ and Er3+) ions, which are doped into i) single‐phase Ga2O3 and ii) dual‐phase Ga2O3 and YF3 nanocrystals (NCs). These NCs are obtained by thermally crystallizing ternary silicate‐ and quinary fluorosilicate‐based glasses, respectively. It is found that the two types of active ions can successfully be doped into Ga2O3 NCs, resulting in enhanced ET between the dopants because of the small separation distance of, e.g., &lt;10 Å, whereas ET is significantly suppressed when Ga2O3 and YF3 NCs are coprecipitated. In this case, the studied rare earth ions have a high propensity for being selectively doped in YF3 NCs. The studied transition‐metal ions can always be found in Ga2O3 NCs irrespective of the presence of the fluoride phase. The selective doping and the ET between the two types of active ions can be controlled simultaneously on annealing. This may allow for the achievement of diverse PL properties, such as ultrabroadband near‐infrared and upconversion‐mediated Stokes emissions.

ICG‐Sensitized NaYF4:Er Nanostructure for Theranostics

AbstractHere lanthanide‐doped luminescent nanoparticles (LNPs) NaYF4:Er conjugated to the indocyanine green dye (ICG) are introduced for theranostics applications in trimodal imaging as well as in photothermal therapy. ICG as a donor with high absorption cross‐section at 808 nm increases excitation efficiency of Er3+ through the energy transfer mechanism and, therefore, significantly enhances both upconverted and Stokes emissions from Er3+ ions in LNPs. Enhanced Stokes emission is used at 1.5 µm for bioimaging in the second near‐infrared wavelength window, which allows deeper penetration in biological media due to reduced scattering. A part of the ICG excitation decays by the competing nonradiating relaxation to produce local heating, which is utilized for photoacoustic imaging as well as for local thermal imaging. All these modalities are demonstrated by in vivo imaging of subcutaneous pancreatic tumor‐bearing nude mice. Furthermore, in the thermal imaging as well as in vitro photocytotoxicity studies, it is shown that the local temperature rise is high enough to be used for highly effective photothermal therapy. Cytotoxicity study on cells using the MTT assay shows the biocompatibility feature of this nanoconstruct. The obtained results demonstrate the potential of ICG‐NaYF4:Er nanoconjugates for multimodal theranostics.

Visible upconversion luminescence mediated by energy transfer in fluorogermanate glass doped with Tm3+ and Ho3+

Multicolor blue (480nm), green (540nm) and red (655nm) upconversion light generation in Tm3+/Ho3+-codoped fluorogermanate glass excited by high-order stimulated Raman scattering Stokes emissions, generated in an optical fiber pumped by a laser operating at 1.064µm, is demonstrated. The excitation route for the 480nm, 650, and 800nm Tm3+ emissions is accomplished through stepwise multiphonon-assisted ground-state, and excited-state absorption of 1.06, 1.12, 1.18, and 1.24µm pump photons. The 540nm emission of Ho3+ ions is effectuated through an initial ground-state absorption (5I8-5I6) in conjunction with energy-transfer Tm3+ to Ho3+ connecting the 5I6 - 5F2, 3K8 followed by rapid multiphonon relaxation to the 5F4, 5S2 green emitting levels. Energy-transfer Tm3+ (3H5-3H6) to Ho3+(5I8-5I6), and Tm3+(1G4) to Ho3+(5F2,3K8), also enhance the holmium ions upconversion excitation process. Pump power dependence of the emitted light, lifetime measurements, as well as the CIE-1931 color coordinates for fixed Tm3+ concentration and varying H3+ content, were also examined and discussed

Cascaded Self-Raman Laser Emitting Around 1.2–1.3 &lt;italic&gt;μ&lt;/italic&gt;m Based on a c-cut Nd:YVO4Crystal

An acousto-optic Q-switched self-Raman laser emitting around 1.2–1.3 μ m based on cascaded conversion with the Raman shifts of 259 and 890 cm−1 was demonstrated in a c-cut Nd:YVO4 crystal. The laser starts with single Stokes emission at 1215 nm. As the incident pump power is increased, Stokes emissions at 1255 and 1316 nm also appear in sequence. When the incident pump power reaches 17.1 W and the pulse repetition frequency is set at 10 kHz, multi-Stokes output is obtained, and the average output power of the laser is 1.02 W, corresponding to a slope efficiency of 9.1%. The multi-Stokes laser output has a pulsewidth of 5.2 ns. Therefore, self-Raman laser lines were enriched with the participation of small Stokes shift of 259 cm−1 in the c-cut Nd:YVO4 crystal.

Stokes and anti-Stokes luminescence in Tm(3+)/Yb(3+)-doped Lu3Ga5O12 nano-garnets: a study of multipolar interactions and energy transfer dynamics.

Nanocrystalline Lu3Ga5O12 garnets doped with Tm(3+)/Yb(3+) ions have been synthesized by a low cost and environmentally benign sol-gel technique and characterized for their structural, Stokes and anti-Stokes luminescence properties. The diffuse reflectance spectra of doped Lu3Ga5O12 nano-garnets have been measured to derive the partial energy level structure of Tm(3+) and Yb(3+) ions and possible energy transfer channels between them. Upon laser excitation at 473 nm, weak red and intense near-infrared Stokes emissions have been observed in the nano-garnets. The decay curves of (3)H4 and (1)G4 levels of Tm(3+) ions and the (2)F5/2 level of Yb(3+) ions have been measured upon resonant laser excitation and are found to be non-exponential in nature due to multipolar interactions. In order to know the kind of multipolar interaction among optically active ions, the decay curves are analyzed through the generalized Yokota-Tanimoto model. Moreover, under 970 nm laser excitation, intense blue anti-Stokes emission is observed by the naked eye in Tm(3+)-Yb(3+) co-doped Lu3Ga5O12 nano-garnets. The results show that as-synthesized nano-garnets may be useful in the field of phosphors and photonics.

Er3 +-doped zinc tellurite glasses revisited: Concentration dependent chemical durability, thermal stability and spectroscopic properties

Tellurite glasses are interesting materials with extensive infrared transmission window, relatively low phonon energy, high refractive indexes and the ability to incorporate reasonably high amount of rare earth ion dopants. These characteristics make them popular candidates for infrared and visible emissions. Particularly, Er3+-doped tellurite glass compositions have been actively studied for broadband near infrared applications where the requirement for low dimension needs to be compensated by higher doping ion concentration. In this work, we revisit Er3+-doped zinc tellurite glasses, which are among the most thermally and chemically stable tellurite compositions. The glasses were prepared by the melt-quenching technique and the favorable effects of increasing dopant concentration on chemical durability, water resistivity and thermal stability (up to 140°C) are discussed. The photophysical properties of the glasses were studied by absorption and luminescence spectroscopic techniques. The Stokes and anti-Stokes emissions of erbium were analyzed and it was verified that the width of the emission band at 1532nm strongly depends on Er3+ concentration varying from 60 to 82nm for 0.5 and 2.5mol% of Er2O3, respectively. The intensity of green and red upconversion emissions was evaluated and the increased efficiency of red emission with increasing concentration is attributed to energy transfer mechanisms between infrared energy levels.

Near-Infrared Emission and Photon Energy Upconversion of Two-Dimensional Copper Silicates

BaCuSi4O10 (Han blue), CaCuSi4O10 (Egyptian blue), and SrCuSi4O10 are pigments found in many ancient artifacts all over the world. Behind their brilliant color, we demonstrate here that these ancient pigments are strong candidates for photonic materials due to their bright Stokes and anti-Stokes emissions. These pigments give near-infrared emissions (NIR) from Cu2+ centered at around 930 nm under excitation of 440–800 nm light. This NIR emission can also be produced by pumping using a NIR laser diode. With the rise of pumping density, the emission bandwidth increases notably and stretches to the visible region, giving rise to bright and broadband photon upconversion (UC). This photon UC process is interpreted in terms of laser-driven blackbody radiation from the ancient pigments.

Intracavity continuous-wave multiple stimulated-Raman-scattering emissions in a KTP crystal pumped by a Nd:YVO(4) laser.

Intracavity continuous-wave (CW) multiple stimulated-Raman-scattering emissions have been successfully demonstrated in a KTP crystal pumped by a Nd:YVO(4) 1064-nm laser for the first time. Three different output couplers (OCs) with high-reflection (HR) coating in the range of 1-1.1, 1-1.13, and 1-1.15 μm are employed in the experiment to generate lasing wavelengths at 1095 (the first-Stokes emission of the 266 cm(-1) Raman shift), 1095 + 1128 (the first- and second-Stokes emission of the 266 cm(-1) Raman shift), and 1095 + 1128 + 1149 nm (the first two Stokes emissions of the 266 cm(-1) Raman shift and the first-Stokes emission of the 694 cm(-1) Raman shift), separately. This Raman laser paves a way to produce more-closely spaced set of CW emission in the green-yellow region.

Dual mode luminescence in rare earth (Er3+/Ho3+) doped ZnO nanoparticles fabricated by inclusive co precipitation technique

Dual excitation properties have been introduced in ZnO nanoparticles (~10 nm) through lanthanide (Er3+/Ho3+) doping by inclusive co precipitation at room temperature. Monophasic hexagonal ZnO nanoparticles form hierarchical micro flowers as a consequence of lanthanide doping. The Stokes and anti Stokes emissions were investigated under UV (399 nm) and IR (980 nm) excitation. The down-conversion emission under band edge excitation is in the blue region and the up-conversion (UC) emission of lanthanide doped ZnO nanocrystals exhibit strong green and red fluorescence bands for ZnO:Er3+ and only green band for ZnO:Ho3+. Post synthesis annealing further improves luminescence properties in ZnO:Er3+ that exhibits triple mode excitation of fluorescence under UV as well as IR wavelengths 980 and 1550 nm, also confirmed by confocal fluorescence mapping. The measured dependence of pump power on UC emission suggest that lanthanide doping in ZnO leads to frequency up-conversion emission via two to three photon absorption processes.

Simultaneous Stokes and Anti-Stokes Lines Operation Within a Yb:YAG Laser at 1050 nm

An intracavity cascaded Raman laser with the Stokes and anti-Stokes emissions from a single KTiOPO4 crystal pumped by a passively <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$Q$ </tex-math></inline-formula> -switched Yb:YAG laser near 1050 nm was demonstrated. A total conversion output power of 666 mW was obtained at a repetition rate of 9.8 kHz with an overall conversion efficiency of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim 3$ </tex-math></inline-formula> %. The shortest pulse duration of the third Stokes radiation near 1148 nm was measured to be 764 ps, giving out a pulse energy of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$13~\mu $ </tex-math></inline-formula> J and peak power of 17.1 kW. Meanwhile, pulse duration of 1.54 ns at anti-Stokes line was also obtained with a peak power of 3.5 kW. The effective Raman gain was estimated to be <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim 2.1$ </tex-math></inline-formula> cm/GW.

Optical-phonon resonances with saddle-point excitons in twisted-bilayer graphene.

Twisted-bilayer graphene (tBLG) exhibits van Hove singularities in the density of states that can be tuned by changing the twisting angle θ. A θ-defined tBLG has been produced and characterized with optical reflectivity and resonance Raman scattering. The θ-engineered optical response is shown to be consistent with persistent saddle-point excitons. Separate resonances with Stokes and anti-Stokes Raman scattering components can be achieved due to the sharpness of the two-dimensional saddle-point excitons, similar to what has been previously observed for one-dimensional carbon nanotubes. The excitation power dependence for the Stokes and anti-Stokes emissions indicate that the two processes are correlated and that they share the same phonon.

Photoluminescence from germanate glasses containing silicon nanocrystals and erbium ions

We report the first observation of photoluminescence enhancement in Er3+ doped GeO2–Bi2O3 glasses containing silicon nanocrystals (Si-NCs) excited by a laser operating at 980 nm. The growth of ≈200% in the intensity of the Er3+ transition 4S3/2→4I15/2 (545 nm) and of ≈100% for transitions 2H11/2→4I15/2 (525 nm), 4F9/2→4I15/2 (660 nm), and 4I5/2→4I13/2 (1530 nm) was observed in comparison with a reference sample that does not contain Si-NCs. The results open a new road for obtaining efficient Stokes and anti-Stokes emissions in germanate composites doped with rare-earth ions.