ABSTRACT The liquid crystal displays (LCDs) based on backlighting technology dominate the flexible display market. However, the overall optical efficiency of conventional LCD systems is generally less than 5%, caused by the polarization conversion process. Therefore, replacing unpolarized backlight with intrinsically polarized emission sources represents a pivotal technological route to eliminate polarizer‐induced energy loss and improve the overall optical efficiency of LCDs. Herein, we adopted a facile electrospun strategy to encapsulate pre‐synthesized CsPbBr 3 nanowires (NWs) into polystyrene (PS) fibers, thereby fabricating the highly stable flexible polarized luminescent CsPbBr 3 NWs@PS fiber film. The resultant CsPbBr 3 NWs@PS fiber film exhibits prominent linearly polarized luminescence behavior, with the degree of polarization (DOP) reaching as high as 0.48. Specifically, the hydrophobic PS sheath acts as a physical barrier that efficiently suppresses ionic migration and concentration quenching effects within the encapsulated CsPbBr 3 NWs, leading to a 7.16‐fold enhancement in photoluminescence (PL) lifetime. In addition, the CsPbBr 3 NWs@PS fibers retain 95% of initial PL intensity after 300 days in an air environment. This work provides valuable experimental evidence and theoretical insights for the rational design and fabrication of high‐performance perovskite‐based highly stable flexible polarized luminescent films, which holds great promise for advancing the development of high‐efficiency LCDs and other polarized optoelectronic devices.
ABSTRACT Optical skyrmions are topologically nontrivial polarization textures with intrinsic robustness under external perturbations, making them promising carriers for disturbance‐resistant optical information transmission. However, existing optical skyrmion generation schemes mostly rely on static optical devices or fixed nanostructures, making high‐speed dynamic switching of the topological state difficult. Here, we propose a high‐speed switchable optical skyrmion encoder based on a compact liquid‐crystal spin‐orbit device. The device employs the in‐plane orientation of liquid crystal molecules to imprint a fixed Pancharatnam‐Berry geometric phase, while an applied voltage rapidly tunes the liquid‐crystal retardance. This electrical control enables reversible switching of the output state from a skyrmionic polarization texture to a uniformly polarized vortex and vice versa. Experimental results show that the device exhibits millisecond electrical response, with bidirectional response times of and ms, corresponding to an ideal cycling rate of approximately Hz, making it the fastest switchable optical skyrmion generator to date, to the best of our knowledge. Furthermore, by exploiting this rapid topological refreshing capability, we demonstrate image encoding and decoding, providing a new liquid‐crystal device platform for high‐speed, refreshable, and disturbance‐resistant topological optical information transmission.
ABSTRACT Blue‐green ultrafast lasers offer great potential for oceanic optical communication, laser fabrication, and scientific research. We present an efficient cascaded harmonic generation based on an ultrafast high‐power thulium‐doped fiber laser (TDFL) and LiB 3 O 5 (LBO)/β‐BaB 2 O 4 (BBO) crystals. By synergistically optimizing the spatio‐temporal power density of the fundamental laser and the nonlinear crystal length configurations, the system delivers average power/pulse duration of 31.5 W/468 fs at 981.3 nm and 16.1 W/489 fs at 490.8 nm, corresponding to ∼50% conversion efficiency for each harmonic stage. In addition, our work demonstrates the beneficial effects of the intrinsic spatiotemporal walk‐off on suppression of back conversion, while spectral and spatial filtering facilitate beam purification and noise reduction during the second harmonic generation (SHG) process. The multiplicative nature of noise transfer in harmonic generations is substantially counteracted by the spectral and spatial filtering, leading to an integrated relative intensity noise (RIN) of 0.15% (10 Hz–10 MHz) and a timing jitter of 1.8 ps (1 kHz–10 MHz) for the 490.8 nm laser at the maximum output power. To the best of our knowledge, this represents the highest output power ever reported for femtosecond lasers in the 0.9 µm and blue‐green wavelength ranges.
ABSTRACT Non‐doped organic light‐emitting diodes (OLEDs) offer simpler fabrication and lower manufacturing costs than traditional doped OLEDs, attracting increasing attention in both scientific research and industrial applications. However, aggregation‐caused quenching (ACQ) and unbalanced carrier transport remain major bottlenecks to achieving efficient non‐doped OLEDs, especially the primary‐blue fluorescent OLEDs. Herein, we report three novel blue or deep‐blue emitters with excellent non‐doped OLED performance of near 15% external quantum efficiency (EQE), which can be assigned to the synergistic contributions of intramolecular hybrid local and charge‐transfer (HLCT) excited state character and intermolecular aggregation pattern. The incorporation of a fluorene π‐bridge in the three molecules not only contributes to the high photoluminescence quantum yield (PLQY), high blue color purity and satisfactory exciton utilization efficiency (EUE), but also to the regulated π‐stacking that gives rise to both light outcoupling efficiency, with horizontal dipole orientation factor (Θ // ) exceeding 90%, and boosted carrier mobilities (at 5.0 × 10 5 V·m −1 , hole: ∼ 2.76 × 10 −5 cm 2 ·V −1 ·s −1 ; electron: ∼ 2.51 × 10 −4 cm 2 ·V −1 ·s −1 ) in non‐doped OLEDs.
ABSTRACT Inorganic scintillators are essential for X‐ray detection and imaging applications, but their rational design remains challenging due to limited experimental datasets and the chemical heterogeneity across oxides, fluorides, chlorides, and iodides, each with distinct luminescence mechanisms. Herein, we develop a machine learning framework based on a Mixture‐of‐Experts Kolmogorov–Arnold Network (MoE‐KAN) to accelerate the discovery of inorganic scintillators with high light yield (LY). By integrating chemistry‐aware gating with KAN‐based expert regressors, MoE‐KAN effectively captures nonlinear composition–property relationships in small and heterogeneous datasets, showing improved generalization over conventional machine learning models and MoE‐MLP on unseen scintillator systems. Through SHAP analysis and symbolic regression, we further distill an empirical composition‐property screening criterion that links LY to the interplay among effective nuclear charge, enthalpy of melting, covalent radius, and Mendeleev chemists sequence. Applying this interpretable strategy to the CsCaCl 3 system, we identify Mn 2+ as the optimal activator and demonstrate, for the first time, its X‐ray scintillation performance: CsCaCl 3 :1%Mn achieves a light yield of 21,577 photons/MeV (∼2.1× commercial BGO) with good dose‐rate linearity and X‐ray imaging capability. This work establishes an interpretable data‐driven route for discovering high‐light‐yield inorganic scintillators under data‐limited conditions.
