Epsilon-near-zero (ENZ) media were demonstrated to exhibit unprecedented strong nonlinear optical properties including giant second-harmonic generation (SHG) due to their field-enhancement effect. Here, on the contrary, we report the quenching of SHG by the ENZ media. We find that when a tiny nonlinear particle is placed very close to a subwavelength ENZ particle, the SHG from the nonlinear particle can be greatly suppressed. The SHG quenching effect originates from the extraordinary prohibition of electric fields occurring near the ENZ particle due to evanescent scattering waves, which is found to be universal in both isotropic and anisotropic ENZ particles, irrespective of their shapes. Based on this principle, we propose a kind of dynamically controllable optical metasurface exhibiting switchable SHG quenching effect. Our work enriches the understanding of optical nonlinearity with ENZ media and could find applications in optical switches and modulators.

金属卤化物钙钛矿太阳能电池已经能够实现25.7%的认证光电转化效率，接近于晶硅太阳能电池26.7%的最高认证效率。众所周知，ABX₃钙钛矿材料的晶体结构组分工程在实现高效和稳定的器件方面发挥着关键作用，尤其是近几年受到研究人员广泛关注的X位卤素阴离子组分工程。最近，研究人员在引入赝卤素阴离子作为钙钛矿晶体的掺杂组分、前驱体添加剂、薄膜后处理材料、电荷传输材料、界面钝化剂以及改性剂等方面开展了多项研究工作，结果证明赝卤素离子修饰是提高器件效率和稳定性的重要策略。本综述详细对比和总结了目前可用于钙钛矿太阳能电池的多种类型的赝卤素离子，并对其影响钙钛矿晶体薄膜形貌、光电特性、载流子迁移特性和器件光伏特性及稳定性等方面的深入机理和作用本质进行了深入总结。同时，本文还对目前尚未被探索开发的赝卤素离子进行了展望和分析，以期在未来研究中能有效促进钙钛矿太阳能电池光伏特性的提升。

Impact and torsion pendulums are applied in impulse coupling experiments of high-energy laser irradiation of space debris. It is difficult to achieve a multi-pulse experiment and thus hard to analyze the multi-pulse impulse coupling effect. Here, we designed a new recoil impulse experimental measurement system of non-contact, multi-degrees of freedom, and multi-pulse irradiation. The system used a low-pressure and low-temperature vacuum chamber to simulate the space environment, the pinning effect of magnetic levitation to achieve aluminum target suspension, and high-speed cameras to record the displacement over time to calculate the impulse of the target. Then the impulse coupling experiment of multi-pulse laser irradiation on the aluminum target was performed. The result shows that the multi-pulse impulse coupling effect is not the linear accumulation of coupling results by every single-pulse and multi-pulse coefficient that decreases with the increase of the number of pulses, and eventually stabilizes as the decrease gets smaller.