提高上转换发光效率是促进上转换发光材料实际应用的关键。在NaErF₄@NaYF₄体系中，惰性NaYF₄壳层可以抑制高组分Er³⁺掺杂下的发光浓度猝灭，其上转换发光主要来源于Er³⁺⁃Er³⁺的能量传递上转换。本文利用共沉淀法制备了Er³⁺和Yb³⁺分区掺杂的NaErF₄@NaYbF₄@NaYF₄核壳结构的纳米颗粒，通过包覆惰性壳层研究Er³⁺⁃Yb³⁺⁃Er³⁺之间的能量传递和反向能量传递过程。由于808 nm波长只能激发Er³⁺而不能激发Yb³⁺，因此在808 nm波长激发下，Er³⁺在惰性壳层的保护作用下将激发态能量传递给Yb³⁺，随后通过反向能量传递回Er³⁺，使得Er³⁺的上转换发光增强。实验结果发现，当中间层Yb³⁺掺杂浓度为100%时，绿色和红色上转换发光最大增强倍数为24.9和9.79。

利用溶剂热法制备了六角相NaYF₄∶20%Yb，2%Er@NaYF₄@NaYbF₄∶0.5%Tm@NaYF₄多层核壳结构稀土掺杂上转换纳米粒子，研究其在低温场（10~295 K）及980 nm激发下分别来自于Er³⁺的绿色与红色以及Tm³⁺的蓝色发光的上转换发光性质。结果显示，绿光强度随温度升高呈现出先增后降的变化趋势，而蓝光强度随温度升高呈现热衰减的趋势。本工作利用发光强度比的测温方法实现了精准的温度测量，相对灵敏度可达3.2%·K^-1。并通过改变外层发光壳层的厚度调节发光强度比，进一步应用于低温场光学防伪。

Precise and ultrafast control over photo-induced charge currents across nanoscale interfaces could lead to important applications in energy harvesting, ultrafast electronics, and coherent terahertz sources. Recent studies have shown that several relativistic mechanisms, including inverse spin-Hall effect, inverse Rashba–Edelstein effect, and inverse spin-orbit-torque effect, can convert longitudinally injected spin-polarized currents from magnetic materials to transverse charge currents, thereby harnessing these currents for terahertz generation. However, these mechanisms typically require external magnetic fields and exhibit limitations in terms of spin-polarization rates and efficiencies of relativistic spin-to-charge conversion. We present a nonrelativistic and nonmagnetic mechanism that directly utilizes the photoexcited high-density charge currents across the interface. We demonstrate that the electrical anisotropy of conductive oxides RuO₂ and IrO₂ can effectively deflect injected charge currents to the transverse direction, resulting in efficient and broadband terahertz radiation. Importantly, this mechanism has the potential to offer much higher conversion efficiency compared to previous methods, as conductive materials with large electrical anisotropy are readily available, whereas further increasing the spin-Hall angle of heavy-metal materials would be challenging. Our findings offer exciting possibilities for directly utilizing these photoexcited high-density currents across metallic interfaces for ultrafast electronics and terahertz spectroscopy.

Aligned SnS nanowires arrays were grown via a simple chemical vapor deposition method. As-synthesized SnS nanowires are single crystals grown along the [111] direction. The single SnS nanowire based device showed excellent response to near infrared lights with good responsivity of 267.9 A/W, high external quantum efficiency of 3.12 × 10⁴ % and fast response time. Photodetectors were built on the aligned SnS nanowire arrays, exhibiting a light on/off ratio of 3.6, and the response and decay time of 4.5 and 0.7 s, respectively, to 1064 nm light illumination.

In this Letter, we propose two crosstalk-aware routing, core, and spectrum assignment (CA-RCSA) algorithms for spatial division multiplexing enabled elastic optical networks (SDM-EONs) with multi-core fibers. First, the RCSA problem is modeled, and then a metric, i.e., CA spectrum compactness (CASC), is designed to measure the spectrum status in SDM-EONs. Based on CASC, we propose two CA-RCSA algorithms, the first-fit (FF) CASC algorithm and the random-fit (RF) CASC algorithm. Simulation results show that our proposed algorithms can achieve better performance than the baseline algorithm in terms of blocking probability and spectrum utilization, with FF-CASC providing the best performance.