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Broadband near‐infrared (NIR) emitting materials have gained considerable attention for their applications in lighting, displays, sensing, bio‐imaging, and optical amplification. Recently, numerous excellent broadband NIR emitting materials are developed by introducing Cr3+, Bi+, or Ni2+ ions to various hosts. However, there is a notable absence of reports on ultra‐broadband NIR emitters spanning the entire telecommunication window as well as the NIR‐I (700–1000 nm) and NIR‐II (1000–1700 nm) biological windows activated by vanadium ions. Herein, the study presents, for the first time to the best of the knowledge, ultra‐broadband NIR emission ranging from 850 to 1600 nm (peaking at ≈1000 nm) at room temperature in vanadium‐doped phosphate glass. Detailed spectra and microscopic structure analysis reveal that two V3+‐emitting centers predominantly contribute to the ultra‐broadband emission, corresponding to 3T2(3F)→3A2(3F) spin‐allowed and 3T2(3F)→1E(1D) spin‐forbidden electron transitions of tetrahedrally coordinated V3+ ions. Notably, the tunability of NIR emission peak is demonstrated by adjusting the local glass structure or the vanadium doping content. Moreover, glass‐converted light‐emitting diodes (gc‐LEDs) are fabricated from vanadium‐doped glass, and the potential applications are demonstrated. The work opens new avenues for the design and fabrication of broadband NIR‐emitting materials and opto‐electronic devices. [ABSTRACT FROM AUTHOR]

Long persistent luminescence materials (LPLMs) are promising candidates for various photonic applications, owing to their ability to store light. In spite of advancements in exploring of new LPLMs, the fabrication of transparent centimeter‐sized LPLMs with pre‐designed shapes, high productivity, long afterglow multicolor luminescence, and high chemical stability, is still challenging. Here, high‐throughput manufacture of translucent crystal‐glass composites via a classical injection molding (IM) technique is demonstrated, in which persistent phosphors (PPs)‐amorphous silica nanoparticles‐polymer composites are molded into different shapes then thermally treated at elevated temperatures to obtain glass composites with embedded PP particles and customized shapes. The structural characterizations endorse that the PP particles are preserved during high temperature sintering, and the resultant crystal‐glass composites combine the unique benefits of both PPs and silica glass. Remarkably, the total production time to manufacture 100 pieces of centimeter‐sized crystal‐glass composites is 35 h, thus enabling high‐throughput production of glass composite articles by the IM method. In addition, the injection molded crystal‐glass composites demonstrate long afterglow multicolor luminescence and ultrahigh chemical durability. This study provides a massive production strategy for the fabrication of translucent and stable multicolor persistent luminescent objects with customized shapes, which can be used in numerous applications. [ABSTRACT FROM AUTHOR]

Phosphor‐in‐silica glass (PiSG) composite is an excellent candidate for highly stable and efficient color converter in high power white light emitting diodes (wLEDs). However, the high‐throughput fabrication of PiSG with different shapes is still challenging for current techniques. Here this study reports the manufacture of transparent PiSG based on YAG:Ce (Y3Al5O12:Ce3+) using injection molding (IM) technique. In this approach, different shapes of centimeter‐sized YAG:Ce‐PiSG pieces are fabricated by using IM of a YAG:Ce/amorphous silica nanoparticles/thermoplastic polymer composite at low temperatures (@ 150 °C) which afterward are debound (@ 600 °C) and densified (@ 1150 °C). Interestingly, the molding time to produce YAG:Ce/silica/polymer green parts is 5 s per piece, implying the capability for high‐throughput production of YAG:Ce‐PiSG. Furthermore, the as‐fabricated YAG:Ce‐PiSG exhibits high luminescence efficiency (>91%) and high chemical/thermal stabilities. Accordingly, high power wLEDs (10 W) are fabricated using the YAG:Ce‐PiSG which demonstrates high luminous efficiency of 144 lm W−1 at 50 mA, closing to that of the wLEDs fabricated by expensive YAG:Ce ceramic plate (i.e., 149 lm W−1 @ 50 mA). The work provides a facile and universal approach for industry‐scale production of PiSG that can be promising for various photonic applications. [ABSTRACT FROM AUTHOR]

The rational control of intrinsic defects in materials can significantly enhance their scientific and technological potentials, but it remains a long‐standing challenge in nanocrystal‐in‐glass composites (NGCs). Herein, a defect engineering strategy mediated by the mixed alkali effect is proposed and experimentally demonstrated for NGCs. Interestingly, the hybridization of large alkali ions can effectively increase the barrier of Li+ migration and reduce the Li‐related defects in LiNbO3 NGC. As a result, a novel LiNbO3 NGC with greatly reduced Li‐related defects, high crystallinity of over 60%, and excellent optical transmission are successfully fabricated. This unique NGC configuration facilitates efficient transverse second harmonic generation (TSHG) in a broad wavelength region. Based on the above effects, a standard TSHG device is fabricated and implemented to monitor ultrashort optical pulses with duration in the order of ≈10−13 s over a broad wavelength region, down to 780 nm. The proposed strategy not only provides a new idea for defect engineering in materials science but also has great significance for boosting the practical applications of NGCs in ultrashort optical pulse monitoring. [ABSTRACT FROM AUTHOR]

Effective online monitoring of the spatial distribution of high‐energy radiation is of significant importance in various fields such as medical imaging, high‐energy physics, and homeland security. However, achieving radiation detectors with both high sensitivity and minimal disturbance is an enormous challenge. The present study introduces a solution to this bottleneck issue through the development of a full‐inorganic scintillating fiber, successfully demonstrating its application in constructing a radiation monitoring device. The scintillating fiber, activated with Ce3+ and fabricated using the melt‐in‐tube approach, is lightweight with a density of 2.5 g cm−3 and exhibits efficient scintillating emission with a light yield of 4000 photons MeV−1. These characteristics enable the achievement of radiation detection with high sensitivity while keeping disturbance to the incident radiation beam at a minimum. Furthermore, 2D and 3D radiation beam monitors are constructed based on these scintillating fibers, facilitating spatial radiation monitoring. The findings demonstrate that full‐inorganic scintillating fibers and devices offer a synergistic combination of high sensitivity and negligible disturbances. This progress not only introduces a novel full‐inorganic fiber for radiation detection but also suggests promising applications in various nuclear fields where 3D radiation beam tracking is essential. [ABSTRACT FROM AUTHOR]

The precise manipulation of neural activity is of great significance to reveal the function of complex neural circuits in brain, especially the mechanism of neurological disorders such as epilepsy, Parkinson's, and Alzheimer's disease. In the past decades, optogenetics has become a powerful tool to investigate the function of neural circuits due to its unique advantages of cell specificity and high spatiotemporal resolution. However, to date, most optogenetic manipulation has been conducted in an open‐loop fashion. The closed‐loop neural modulation is still an important task. Here, a closed‐loop optogenetic modulation system is developed for ultra‐fast, ‐accurate, and ‐stable manipulation of neural activities in behaving mice. Specifically, this system is mediated by a functional fiber probe with excellent low optical loss (0.052 dB cm−1 at 589 nm) and electrical impedance (5.40 MΩ µm−2 at 1 kHz). In vivo electrophysiology and behavioral experiments demonstrated that the system can be successfully applied for the identification and intervention of seizures in epilepsy mice with high efficiency. It is envision that the closed‐loop manipulation system has promising applications in brain science, neuroscience, and neuromodulation therapies. [ABSTRACT FROM AUTHOR]

Excitation polarized upconversion luminescence (EPUL) from lanthanide ions has attracted considerable attention due to its wide applications in microfluidics, single particle tracking, security inks, and cell internal viscosity testing. However, controlling the degree of excitation polarization (DOEP) of the EPUL remains a significant challenge. Here, the modulation of the DOEP (from 0 to 0.5) of the EPUL from Er3+ doped single nanorods by changing the concentration of doped Er3+, Yb3+, or Mn2+ is systematically studied. By analyzing the lifetimes and disproportionate changes in luminescence intensities, it is found that optimizing Er3+, Yb3+, or Mn2+ concentration can reduce non‐radiative transition and population density in excited states, leading to the enhancement of the DOEP under a good alignment of transition dipoles. Furthermore, the possibility of anti‐counterfeiting based on such tunable EPUL is illustrated. Three kinds of fine patterns with a small size of 10 µm are realized by assembling the single nanorods accurately via optical tweezers. The patterns and their EPUL guarantee double protection for the feasibility of anti‐counterfeiting. The findings of this study offer insights into the EPUL from lanthanide ions and provide a microscale platform via the EPUL for the application of multidimensional information encoding and reconfigurable double anti‐counterfeiting. [ABSTRACT FROM AUTHOR]

The outstanding performance of halide perovskite makes it one of the champion materials for applications in optoelectronic devices. However, the stability of perovskites limits their practical applications. Among all the factors influencing the stability of perovskites, defects are one of the key factors. Till now, many chemical methods have been proposed to passivate defects. Nevertheless, there is still a lack of in situ passivation methods without the change of the composition of perovskites. Here, it is found that the external electric field can passivate the defects in FPEA2PbI4 (FPEAI = 2‐(4‐Fluorophenyl)ethylamine Hydroiodide) film in a capacitive device at 78 K, and the PL intensity can be enhanced greatly. A "charge‐soaking effect" can be observed, that is PL intensity continues to increase for a long time after removing the electric field. Besides the emission peak from free exciton, two other peaks at the lower energy side from defect‐bound excitons are observed. They are more susceptible to the external electric field than the free exciton. This work will deepen the understanding of exciton behavior and the interaction of electric field with excitons in two–dimensional (2D) hybrid perovskites for efficient light–emitting diodes (LEDs) and electrically pumped lasers. It provides a new in situ passivation method of perovskites for practical applications. [ABSTRACT FROM AUTHOR]

The ability to modulate the nonlinear optical (NLO) response of low‐dimensional metal oxides is highly desirable for diverse applications. It is shown here that the irradiation of a dispersion of 2D oxide (MoO3) nanosheets (NSs) by femtosecond laser pulses enables simultaneous scissoring of the NSs to form well‐dispersed MoO3 quantum dots (QDs) and the modulation of the NLO response in the visible and near‐infrared (NIR) regions. The inversion of the absorptive nonlinearity is observed combined with a larger enhancement of NLO response in the laser‐irradiated MoO3−x NSs and the as‐generated QDs, which is associated with the steady laser‐deprival of oxygen atoms and the resultant localized surface plasmon resonance due to electron doping. By leveraging the sub‐picosecond NLO response of the plasmonic MoO3−x QDs, the development of ultrafast optical switches is demonstrated for ultrashort pulse laser generation based on fiber lasers operating in the NIR regions. Furthermore, the strong field enhancement of these non‐noble metal plasmonic QDs is exploited for the fabrication of substrates for surface‐enhanced Raman scattering, which demonstrate a detection limit down to the part‐per‐billion level. This work delineates an efficient strategy for creating plasmonic oxide QDs with strong NLO response that is attractive for photonic applications. [ABSTRACT FROM AUTHOR]

Broadband near‐infrared (NIR) phosphors have recently received considerable attention in spectroscopy technology fields, but designing inexpensive, emission peaks centered above 800 nm, and multimodal broadband NIR luminescence material still remains a great challenge. Here, by selecting stannate compound Mg2SnO4 (MSO) as the host, a kind of broadband NIR phosphor MSO:Cr3+ with multimode luminescence properties is reported. The designed material exhibits an emission peaking at 800 nm and a full‐width at half maximum of 180 nm (≈2730 cm−1). The site occupation of Cr3+ in MSO is unraveled by density functional theory calculation. The constructed NIR light‐emitting device based on MSO:Cr3+ displays a high NIR output power of 187.19 mW@100 mA and remarkable photoelectric efficiency of 13.67%, and its multifunctional applications in information encryption, non‐destructive detection, and so on are also demonstrated. Additionally, through defect site reconstruction, MSO:Cr3+ presents superior broadband NIR persistent luminescence (PersL) properties with PersL duration time longer than 50 h. This work provides a feasible strategy to develop intelligent optical material integrated with multimodal luminescence through low‐cost stannate compounds as the host toward versatile applications such as non‐destructive detection and bioimaging. [ABSTRACT FROM AUTHOR]

The ability for simultaneous modulation and monitoring of neural activities in deep tissues and at the single‐cell level merits significant scientific and technological potential, yet is met with limited success using conventional probes. Here, a new type of tiny multimaterial glass fiber probe is proposed and successfully constructed with the combination of robust mechanical response, strong light‐delivering ability, and excellent electrochemical properties, based on high throughput and scalable co‐drawing strategy. Guided by the multimaterial integration principle, the configuration of the probes can be rationally tuned including their material combination, physical size, the number and spatial distribution of the electrode, and even the waveguide structure. The bending stiffness, optical loss, and electrical impedance can be controlled to be larger than 4900 N m−1 and as small as 0.01306 dB cm−1 and 19.63 MΩ µm2 at 1 kHz, respectively. To prove the utility, it is demonstrated that the probes allow for simultaneous deep neural stimulation and detection for more than 2 weeks at a single cellular level. This work not only promotes the development of neuroscience and brain science through the ability to manipulate neural circuits in the deep brain but also provides new directions for expanding the scope of functional fibers. [ABSTRACT FROM AUTHOR]

Spinel configuration is a kind of broadly considered host candidate when designing persistent luminescence (PersL) materials due to the easy generation of vacancies and anti‐site defects. Here, a new strategy of defect enrichment for the activation of PersL is proposed, and in contrast to the spinel configuration, it is demonstrated that the crystal structure of near inverse spinel ensures more numerous defects to activate the near‐infrared (NIR) PersL of Fe3+. Fe3+‐doped MgGa2O4 displays the PersL band in the range of 600 to 900 nm and possesses a super‐long PersL duration time >15 h. The optical analysis and the calculation of density functional theory unravel that the near inverse spinel structure can lower the carrier transfer barriers to accelerate the formation of carrier trap states within the bandgap. Therefore, more numerous defects in this structure may participate in the trapping and de‐trapping process by comparison with the normal spinel configuration. These findings are expected to accelerate the development of new PersL materials through Fe3+ doping toward versatile biological applications in NIR window. [ABSTRACT FROM AUTHOR]

Rare earth doped down‐conversion (DC) materials, due to their unique spectral conversion characteristics, are promising candidates for narrow band solar‐blind ultraviolet (UV) light detection devices. Herein, an enhanced capture device for broadband solar‐blind UV light is constructed by combining an ordinary semiconductor with a DC spectrum converter, the essence of which is to introduce the appropriate alkali‐metal ions (Li+, Na+, and K+) into DC layer. Europium‐doped organic–inorganic composite films are used as spectral converters because of their excellent DC characteristic, which can convert broadband solar‐blind UV incident illumination into visible light suitable for capture by light dependent resistor (LDR). Interestingly, the spectral conversion efficiency is positively correlated with the capture ability of broadband solar‐blind UV photons. The introduction of alkali‐metal ions in the DC layer enhances the photon detection efficiency with an increase rate of around 200%, which is attributed to alkali‐metal ions changing the local crystal field symmetry around the Eu3+ emitter and distorting the matrix crystal of Y2O3, thus increasing the probability of intra‐4f electron transition. These results signify that the present rare‐earth doped DC luminescent materials are promising building blocks for assembly of high‐performance broadband solar‐blind UV detector. [ABSTRACT FROM AUTHOR]

Fiber lasers, owing to the high beam quality and super robustness, are widely used in fields from optical communications, fiber sensing, biomedicine to material processing. The use of glass fibers as the gain medium has, however, posed a strong obstacle for improving efficiency and, especially, achieving efficient lasing action in the mid‐infrared (MIR) region, because of the relatively large nonradiative energy loss. Here, the fabrication of a Tm3+‐doped tellurate glass‐ceramic (GC) fiber is demonstrated, which enables enhanced lasing action at ≈2 µm. Compared with the as‐prepared fiber, the optical conversion efficiency of GC fiber is increased from 8.8% to 14.1%. The microstructure and spectral characterization analyses suggest that the improvement of the laser performance in GC fiber is induced by the significant change of the local environment surrounding Tm3+ ions due to the formation of nanocrystals within the glass fibers. Moreover, the developed GC fiber also enables Q‐switched pulsed laser output at ≈2 µm with a pulse energy of 3.2 J and pulse width of 4.1 ns. The results demonstrated here may have strong implications in the development of MIR fiber lasers and the applications of GC fibers in MIR photonics. [ABSTRACT FROM AUTHOR]