AlGaN-based light-emitting diodes (LEDs) on offcut substrates enhance radiative emission via forming carrier localization centers in multiple quantum wells (MQWs). This study introduces the carrier transport barrier concept, accessing its impact on the quantum efficiency of LEDs grown on different offcut sapphire substrates. A significantly enhanced internal quantum efficiency (IQE) of 83.1% is obtained from MQWs on the 1° offcut sapphire, almost twice that of the controlled 0.2° offcut sample. Yet, 1° offcut LEDs have higher turn-on voltage and weaker electroluminescence than 0.2° ones. Theoretical calculations demonstrate the existence of a potential barrier on the current path around the step-induced Ga-rich stripes. Ga-rich stripes reduce the turn-on voltage but restrict sufficient driving current, impacting LED performance.

Toroidal multipole is a special current distribution that has many different characteristics from electric multipole and magnetic multipole distributions. Because of its special properties, the toroidal dipole is a research hotspot in the field of metamaterials and nanophotonics. However, the low scattering of the toroidal dipole moment makes its excitation a challenging task. At present, there are relatively few studies on its specific engineering applications. In this paper, by slotting in the rectangular cavity, the excitation of an equivalent toroidal dipole is successfully achieved over a wide frequency range of 53–58 GHz. Results indicate that under the action of the toroidal dipole, the TE10 mode electromagnetic waves transmitted in the rectangular waveguide are converted into vector beams and are radiated outwards. Further adjusting the spatial distribution of the magnetic dipoles in the toroidal dipoles yields results that indicate that the resonance mode in the slot is still dominated by the magnetic toroidal dipole moment, and the electromagnetic waves radiating outward are vortex beams carrying vector polarization. The scattered energy of each dipole moment inside the antenna is calculated. This calculation verifies that the mass of the vector beam and vector vortex beam is closely related to the toroidal dipole supported by this antenna. The proposed structure can be applied to explorations in vortex filtering, in photon entanglement, and in the photonic spin Hall effect.

基于ABX₃晶体结构材料的新型钙钛矿太阳能电池具有光电转换效率高、可溶液加工以及低温工艺兼容等优势。与此同时，利用钙钛矿材料合成方法简单、带隙可调以及膜厚和透过率可控等优点制备的半透明钙钛矿太阳能电池为薄膜光伏的发展带来了新的契机，在建筑集成光伏和叠层光伏等领域应用前景广阔。开发高效且高稳定的半透明钙钛矿太阳能电池已成为目前光伏领域的研究重点。本文系统综述了半透明钙钛矿太阳能电池的各功能层（钙钛矿光活性层、电荷传输层和电极）材料选择、光学特性调控、电学特性优化以及制备工艺调控等技术策略，同时提出了对半透明钙钛矿太阳能电池未来发展的一些展望。

设计了一种金属/介质/金属复合光栅与梯度超表面相结合的多功能器件。通过复合光栅的非对称结构实现光的非对称传输，当调制后的波矢量与表面等离极化激元的波矢量相匹配时，金属光栅激发的表面等离极化激元产生单波段光传输；通过梯度超表面实现光的异常反射。当x偏振态光波入射时，不同入射方向可在不同波段激发表面等离极化激元，由于上下光栅的不同周期和非对称的介质环境，光栅可分别在1 128 nm和1 550 nm处实现高透射率；另外在反向入射方向，该器件在1 300~1 400 nm整个波段表现为零吸收，反射率大于90%，可作为反射器。当y偏振态光波入射时，在反向入射方向器件通过相位梯度超表面实现异常反射。该结构可为各种偏振相关的多功能器件和集成光学元件提供参考。