Photoelectric logic gates (PELGs) are the key component in integrated electronics due to their abilities of signal conversion and logic operations. However, traditional PELGs with fixed architectures can realize only very limited logic functions with relatively low on–off ratios. We present a self-driving polarized photodetector driven by the Dember effect, which yields ambipolar photocurrents through photonic modulation by a nested grating. The ambipolar response is realized by exciting the whispering-gallery mode and localized surface plasmon resonances, which leads to reverse spatial carrier generation and therefore the contrary photocurrent assisted by the Dember effect. We further design a full-functional PELG, which enables all five basic logic functions (“AND”, “OR”, “NOT”, “NAND”, and “NOR”) simultaneously in a single device by using one source and one photodetector only. Such an all-in-one PELG exhibits a strong robustness against structure size, incident wavelength, light power, and half-wave plate modulation, paving a way to the realization of ultracompact high-performance PELGs.

Active devices have drawn considerable attention owing to their powerful capabilities to manipulate electromagnetic waves. Fast and periodic modulation of material properties is one of the key obstacles to the practical implementation of active metamaterials and metasurfaces. In this study, to circumvent this limitation, we employ a cascaded phase-matching mechanism to amplify signals through spatiotemporal modulation of permittivity. Our results show that the energy of the amplified fundamental mode can be efficiently transferred to that of the high harmonic components if the spatiotemporal modulation travels at the same speed as the signals. This outstanding benefit enables a low-frequency pump to excite parametric amplification. The realization of cascaded parametric amplification is demonstrated by finite-difference time-domain (FDTD) simulations and analytical calculations based on the Bloch–Floquet theory. We find that the same lasing state can always be excited by an incidence at different harmonic frequencies. The spectral and temporal responses of the space-time modulated slab strongly depend on the modulation length, modulation strength, and modulation velocity. Furthermore, the cascaded parametric oscillators composed of a cavity formed by photonic crystals are presented. The lasing threshold is significantly reduced by the cavity resonance. Finally, the excitation of cascaded parametric amplification relying on the Si-waveguide platform is demonstrated. We believed that the proposed mechanism provides a promising opportunity for the practical implementation of intense amplification and coherent radiation based on active metamaterials.

为了实现熔石英元件的高效低缺陷加工，研究了基于磁辅助抛光技术的元件材料去除特性和表面质量形成机制。采用不同抛光间隙和不同铁粉体积比的磁性抛光液对研磨后的熔石英元件进行磁辅助抛光，并对元件材料去除率、抛光斑轮廓、表面粗糙度和透过率进行评价，结合空间磁感应强度仿真和抛光压力分析，确定加工参数对元件加工效率和表面质量的影响规律。结果表明：材料深度去除率随空间磁感应强度的增强呈幂函数上升且随抛光液中铁粉体积比增加而显著提升，低空间磁场强度和低铁粉体积比的抛光液有利于促进以化学去除为主的磁辅助弹性抛光从而获得光洁表面。小抛光间隙（0.5 mm）及高铁粉体积比（14.18%）的抛光液可实现最大材料深度去除率0.439 2 μm/min和体积去除率1.49×10^-4 mm³/min，大抛光间隙（1.5 mm）及低铁粉体积比（9.93%）的抛光液能够获得粗糙度R_a低至8.1 nm的光滑表面。

在某些类型装备的修理过程中，需对装备进行分解，更换故障件后再进行装配。这类装备在生产时使用了多种胶黏剂，修理时需将密封胶清除干净并在装配时重新封胶。已有的修理工艺均采用人工除胶，清除效率低且除胶效果一般。激光清洗技术是一种新型表面清洗技术，具有清洗效率高、清洗精度高等特点，已广泛应用于金属材料表面氧化物清洗、飞机蒙皮清洗、半导体晶圆清洗等领域。对激光清洗技术在某些类型装备修理中应用的可行性进行了研究，对比了不同基底材料、不同胶黏剂类型、不同激光脉冲能量的清洗效率及清洗效果。结果表明，激光清洗技术可清洗金属、玻璃等表面的胶黏剂，但会对木材、电路板等基底材料造成不可逆的损伤。