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Transparent, inorganic composite materials are of broad interest, from structural components in astronomical telescopes and mirror supports to solid-state lasers, smart window devices, and gravitational wave detectors. Despite great progress in material synthesis, it remains a standing challenge to fabricate such transparent glass composites with high crystallinity (HC-TGC). Here, we demonstrate the co-solidification of a mixture of melts with a stark contrast in crystallization habit as an approach for preparing HC-TGC materials. The melts used in this approach are selected so that glass formation and crystal precipitation occur simultaneously and synergistically, avoiding the formation of interfacial cracks, residual pores, and delamination effects. Using this method, various unusual hybridized HC-TGC materials such as oxychloride, oxybromide, and oxyiodide composite systems were fabricated in dense, bulk shapes. These materials exhibit intriguing optical properties and neutron response-ability. Using such HC-TGC materials, we develop a neutron detector and demonstrate the application for efficient neutron monitoring and even single neutron detection. We expect that these findings may help to bring about a generation of fully inorganic, transparent composites with synergistic combinations of conventionally incompatible materials. Transparent composites are significant for various applications. Here, the authors propose the co-solidification strategy of crystal and glass melts for preparing transparent glass composite with high crystallinity and apply for neutron detection. [ABSTRACT FROM AUTHOR]

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]

The rapid development of emerging technologies observed in recent years, such as artificial intelligence, machine learning, mobile internet, big data, cloud computing, and the Internet of Everything, are generating escalating demands for expanding the capacity density, and speed in next‐generation optical communications. This poses a significant challenge to existing communication techniques. Within this context, the integration of near‐infrared broadband, tunable, and high‐gain luminescent materials into silicon optical circuits or fiber architectures to transmit and modulate light shows enormous potential for advancing next‐generation communication techniques. Here, this review provides an overview of the recent breakthroughs in near‐infrared luminescent epitaxial/colloidal quantum dots, and metal‐active‐center‐doped materials for broadband optical amplifiers and tunable lasers. We also expound on efforts to enhance the bandwidth and gain of these materials‐based amplifiers and lasers, exploring the challenges associate with developing ultra‐broadband and high‐speed optical communication systems. Additionally, the potential applications in Fifth Generation Fixed Networks, integration with 5G and 6G wireless networks, compensation for current Si electronic based CMOS for high computing capability, and the prospects of these light sources for next‐generation optoelectronic devices are discussed. [ABSTRACT FROM AUTHOR]

Lanthanide doped nanoparticles (NPs) exhibit tunable X‐ray‐excited optical luminescence and X‐ray‐excited persistent luminescence (XEPL), holding broad prospects for applications in display/anti‐counterfeiting and X‐ray imaging. The development of effective strategies for multi‐dimensional applications based on lanthanide‐doped fluoride NPs are a constant challenge. Here, core–shell structured fluoride NPs, in which the heavy metal fluoride shell effectively suppresses the non‐radiative relaxation and simultaneously improve the X‐ray absorption of the shell are designed and fabricated. Under X‐ray irradiation, the developed NPs exhibit an increased number of secondary electrons which migrate to Er3+ centers at the interface and greatly improve the XEPL intensity. Additionally, the introduction of Mn2+ further enhances the XEPL intensity and offers an effective route to control the red‐green ratio of the upconversion spectrum. The NPs co‐doped with Mn2+ exhibit a bright green XEPL under X‐ray irradiation and a red emission under 1532 nm laser excitation. It is further validated that these NPs can be utilized for advanced anti‐counterfeiting and high‐resolution delayed imaging based on a film containing NPs as a scintillation screen. These findings suggest a new strategy of designing Er3+ doped NPs for multi‐dimensional applications. [ABSTRACT FROM AUTHOR]

Phosphor‐converted light‐emitting diodes (pc‐LEDs) are efficient and cost‐effective ultrabroadband light sources for miniaturizing various optical systems, but they exhibit poor optical performance due to the lack of efficient near‐infrared (NIR) phosphors with a wide spectral coverage of 700−1100 nm. Although germanate oxides are a promising class of host materials for Cr3+ to generate broadband NIR light, the preferred formation of [CrO4]4− and the high vapor pressure of Ge element cause these Cr3+ activated phosphors to suffer from low internal quantum efficiency (IQE) and poor thermal stability. Here, highly efficient (IQE > 90%) and thermally stable broadband NIR emission of Cr3+ in the germinate garnet Ca2LuMgScGe3O12 (CLMSG) are obtained by exploiting a two‐step sintering method to achieve full reduction of Cr4+ to Cr3+. Further, efficient energy transfer from Cr3+ to Yb3+ is leveraged to significantly improve the emission intensity of CLMSG:Cr3+ in the shortwave infrared range of 900−1100 nm. Finally, an ultrabroadband NIR pc‐LED with a high NIR conversion efficiency (21.5%@10 mA) and high NIR power (116.4 mW@350 mA) is demonstrated to verify the strong capability of CLMSG:Cr3+, Yb3+ in blue‐to‐NIR light conversion. The results open up new ways to realize efficient ultrabroadband NIR‐emitting materials. [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 construction of active materials with controllable optical response facilitates the development of advanced photonic devices. However, the achievement of robust active materials with wide wavelength tunable and broadband emission remains a great challenge, mainly due to the fixed energy levels of conventional active dopants and limited inhomogeneous broadening in common hosts. Here, the study proposes that the cluster in the mesoscopic scale of ≈1 nm may break this bottleneck issue and demonstrate a strategy for the management of photon emission by engineering the cluster evolution. The amorphous glass as the host to tailor the characteristic configuration of Te clusters from 1 to 2 nm by control of the topological structures in glass is employed. Impressively, it presents a distinct optical response totally different from the conventional active centers and this enables to construct of active photonic glass with continuously tunable emission from 888 to 1064 nm. More importantly, Te cluster‐activated photonic glass fibers are fabricated and the broadband on‐off gain is successfully achieved. Furthermore, benefiting from the unique tunable emission, novel near‐infrared devices are constructed and their application in imaging is demonstrated. The approach of cluster engineering mediated tunable optical response is believed to bring new opportunities for developing advanced photonic devices. [ABSTRACT FROM AUTHOR]

Transparent glasses are ideal and robust hosts for a range of emission centers, while the simultaneous manipulation of the temporal and spectral characteristics of emission remains a tremendous challenge for inorganic glasses. Here, the development and functionalization of melt‐quenched transparent coordinate polymer glasses with a tailorable ultralong room‐temperature phosphorescence are demonstrated. Dynamic modulation of the phosphorescence is achieved by utilization of the high molecular rigidity and manipulation of the spin‐orbital coupling effects within the glass systems. By introducing dye molecules into the glasses, Phosphorescence resonance energy transfer from the glass matrix to the dye molecules is exploited and controllable multicolor long‐lived luminescence is demonstrated. Further design of the component and concentration of the encapsulated dyes allows for wavelength‐tunable long‐lived delayed fluorescence via an efficient delayed sensitization process, featuring a tunable emission spectrum covering a wide range from 520 to 630 nm. Leveraging the multiple spectral tuning channels of the hybrid glass, multi‐mode optical information storage, and dynamic anti‐counterfeiting applications are further demonstrated. This work provides a new hybrid material platform and design methodology for realizing lifetime‐adjustable and wavelength‐tunable long‐lived luminescence, which can find wide applications in time‐rsesolved information display, high‐density information storage, and dynamic anti‐counterfeiting. [ABSTRACT FROM AUTHOR]

Near‐infrared (NIR) photonic materials find extensive applications across important fields such as telecommunications, laser radar, and atmospheric remote sensing. In particular, photonic materials activated by main group elements, which exhibit unique spectral features including ultra‐broadband tunable luminescence and long lifetime, have become rising stars in NIR emitting dopants. In this review, the energy level characteristics of the p‐electrons to gain insight into the fundamentals of the NIR optical response from the main group elements are first introduced. Next, the NIR luminescence properties of the main group elements are discussed. Then, the strategy for the design of main group elements activated materials with the desired properties based on local chemical environment engineering is proposed. In addition, recent advances in the applications of main group element (excluding bismuth) activated materials are highlighted. Furthermore, the key scientific issues that urgently need to be solved for such materials, such as the detailed luminescence mechanism are highlighted. Anticipation also extends to the future research trends in this exciting field, including the ways for enhancing luminescence efficiency and extending spectral region, and the efforts for implementing these advancements in novel cutting‐edge technologies like photovoltaics and biomedicine. [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]

In recent years, there has been much interest in inorganic perovskite nanocrystals (NCs) because of their extensive tunability over the visible range, high quantum yield (QY), and photoluminescence (PL). Inorganic perovskite was considered to be the photoactive material for photovoltaic cells because of its excellent photoelectric qualities. The next generation of high-performance solar cells was thought to benefit most from all-inorganic perovskite due to its long electron–hole diffusion length, high carrier mobility, and broad absorption spectrum. In this paper, femtosecond (fs) laser direct writing technology was used to accomplish spatially selective crystallization of CsPbBrxCl3−x (x = 0–3) NCs in precursor glass. By modifying the laser parameters, the size of the precipitated NCs could be regulated, and the photoluminescence of the NCs could be adjusted from blue to green. The optical properties and morphology of the NCs were analyzed by PL spectra and transmission electron microscopy (TEM). Based on fs laser-induced local crystallization, a linear array-based solar concentrator was processed in CsPbBrxCl3−x (x = 0–3) precursor glass and showed higher photoelectric conversion efficiency than that with the bulk glass sample. [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]

In the digital era, the need for high‐density data storage techniques has become increasingly imperative. To address this, the study has demonstrated a multi‐dimensional shingled optical recording technique, utilizing femtosecond laser‐induced nanostructures in silica glass. The evolution of the bulk nanostructures is investigated on a pulse‐by‐pulse basis using multiple microscopic analysis techniques. The formation of the nanostructures is attributed to a self‐adaptive near‐field anisotropic nanostructuring process. Furthermore, it is shown that writing in a 3D shingled configuration significantly reduces the volume per data voxel to a size of 500 nm × 500 nm × 1.0 µm, surpassing the diffraction limit. This reduction is achieved even when employing an infrared laser and a relatively low numerical aperture objective lens. As a result, the approach increases the data storage capacity by at least two orders of magnitude compared to conventional techniques. The work paves the way for advanced shingled optical recording techniques offering ultra‐dense capacity, ultra‐long lifetime, and low energy consumption. [ABSTRACT FROM AUTHOR]

Glass ceramics may exhibit enhanced functionalities compared to the glass and crystal counterparts due to the synergistic effect with the "1+1 > 2" feature in a cooperative manner. Nonlinear optical property is expected to be next breakthrough in presenting synergistic effect in glass ceramics. In this article, we give a comprehensive review of the recent progress of the development in nonlinear glass ceramics with unique photonic domain structure, emphasizing their synergistic effect in nonlinear response. The applications in photonics of the nonlinear glass ceramics are also described. Finally, we also present the opportunities and challenges for further exploring synergistic effect in nonlinear response in glass ceramics. [ABSTRACT FROM AUTHOR]

With the rapid development of 5G networks, the Internet of Things, and new‐generation of AI, there are considerable demands on expanding the capacity of contemporary optical fiber communication systems. One of the most effective avenues involves the extension of the bandwidth of Er‐doped fiber amplifiers, but with limited success. Herein, an Er‐activated hybridized glass fiber are reported, which can help realize broadband telecommunication. The effect of element hybridization on the bandwidth of Er‐activated fiber is clarified and the structure‐optical response relationship is established. A two‐step deposition approach is proposed to overcome the immiscibility barrier of different hybridized elements, and Er‐activated fiber with uniform doping is constructed. The activated fiber presents excellent compatibility with commercial telecommunication systems, providing a small signal gain of >13 dB in the whole L‐band range and a maximum gain of 28 dB. Furthermore, the Er‐activated fiber amplifier device is successfully developed. It exhibits outstanding optical amplification performance with gain >24 dB in the range of 1580–1624 nm, gain fluctuation less than ±0.9 dB, and noise figure <6.5 dB. The results not only provide a new strategy for developing novel active broadband optical fibers, but a valuable solution for new‐generation large‐capacity optical fiber communication systems. [ABSTRACT FROM AUTHOR]

Bismuth (Bi)-doped glasses with broadband near-infrared (NIR) emission have been drawing increasing interest due to their potential applications in tunable fiber lasers and broadband optical amplifiers. Yet, the realization of highly efficient and ultra-broadband Bi NIR emission covering the whole telecommunication window remains a daunting challenge. Here, via rationally controlling the content of Al2O3 to control the local environment and structural defect states around the Bi NIR active centers (BACs), various luminescence centers can coexist stably in a glass matrix. Consequently, tunable ultra-broadband multi-band NIR emission with four emission bands at ∼924, ∼1154, ∼1265, and ∼1516 nm was achieved in a Bi-doped germanate glass under single wavelength excitation. More importantly, such ultra-broadband multi-band Bi NIR emission with excellent thermal stability can be well retained after the glass was drawn into an optical fiber by a rod-in-tube method. The fibers show an obvious broadband ASE spectrum spanning a range of 1000–1600 nm. This work is helpful for understanding the mechanism of Bi NIR emission and offers a simple and feasible method for developing novel photonic devices with ultra-broadband Bi NIR emission. [ABSTRACT FROM AUTHOR]

Square-root topological insulators recently discovered are intriguing topological phases. They possess topological properties inherited from the squared Hamiltonian and exhibit double-band structures. The mechanism of the square root was generalized to 2n-root topological insulators, giving rise to more band gaps. In this study, we describe the experimental realization of one-dimensional 2n-root topological insulators in photonic waveguide arrays using the archetypical Su-Schrieffer-Heeger (SSH) model. Topological edge states with tunable numbers are clearly observed under visible light. In particular, we visualized the dynamic evolutions of the light propagation by varying the sample lengths, which further proved the localization and multiple numbers of edge states in 2n-root topological systems. The experiment, which involves constructing 2n-root topological photonic lattices in various geometric arrangements, provides a stable platform for studying topological states that exhibit a remarkable degree of flexibility and control. [ABSTRACT FROM AUTHOR]

Laser‐induced periodic surface structure (LIPSS) can form structural color on the metal surfaces with high production efficiency and thermal stability, and has been used in various industrial applications such as unfaded color marking and anti‐counterfeiting. Herein, a novel fabrication scheme of multilayer LIPSS is proposed by multiple writing in situ with changing the laser polarization direction, to exhibit an effect of color superposition. To verify this approach, the color formation mechanism of LIPSS on the stainless‐steel surface is analyzed by finite‐element numerical calculation and reveals that the high‐angular dispersion of LIPSS is mainly the result of optical diffraction occurring on the surface of periodic structures. The relationship between the angular dispersion of multilayer LIPSS and laser‐processing parameters is established. Through the proposed multilayer LIPSS coloring technology, vivid full‐color patterns on the steel surface are demonstrated, and the in situ superposition of three‐layer graphs is realized, which can greatly enrich the color levels and be competitive in industrial applications. [ABSTRACT FROM AUTHOR]