In this work, we reported a high-performance-based ultraviolet-visible (UV-VIS) photodetector based on a TiO₂@GaO_xN_y-Ag heterostructure. Ag particles were introduced into TiO₂@GaO_xN_y to enhance the visible light detection performance of the heterojunction device. At 380 nm, the responsivity and detectivity of TiO₂@GaO_xN_y-Ag were 0.94 A/W and 4.79 × 10⁹ Jones, respectively, and they increased to 2.86 A/W and 7.96 × 10¹⁰ Jones at 580 nm. The rise and fall times of the response were 0.19/0.23 and 0.50/0.57 s, respectively. Uniquely, at 580 nm, the responsivity of fabricated devices is one to four orders of magnitude higher than that of the photodetectors based on TiO₂, Ga₂O₃, and other heterojunctions. The excellent optoelectronic characteristics of the TiO₂@GaO_xN_y-Ag heterojunction device could be mainly attributed to the synergistic effect of the type-Ⅱ band structure of the metal–semiconductor–metal heterojunction and the plasmon resonance effect of Ag, which not only effectively promotes the separation of photogenerated carriers but also reduces the recombination rate. It is further illuminated by finite difference time domain method (FDTD) simulation and photoelectric measurements. The TiO₂@GaO_xN_y-Ag arrays with high-efficiency detection are suitable candidates for applications in energy-saving communication, imaging, and sensing networks.

为解决低照度环境下拍摄的图像对比度低、噪声强等问题，提出了基于四稳随机共振的图像增强方法。从产生随机共振的噪声与非线性相互作用出发，构建了非线性的四稳系统并分析其Kramers逃逸率，采用方差作为图像随机共振的衡量指标，建立了系统输出图像方差与噪声强度的近似解析表达式，研究了四稳随机共振在图像增强中的应用。理论分析与数值仿真结果表明，四稳系统输出图像的方差随噪声强度的变化呈现单峰特性，存在图像随机共振现象，且四稳系统产生的共振峰更高，共振效应更强。结合主观评价和客观评价指标，与直方图均衡化、单尺度Retinex、MSRCR和双稳系统进行了比较，结果表明四稳随机共振增强后图像的视觉效果最佳，信息熵为7.7，噪声方差小于0.002，相比于双稳随机共振分别提高了5%和38%。四稳系统更强的随机共振效应能进一步提高图像质量，在低照度图像增强方面更具优势。