Narrowband photodetection is an important measurement technique for material analysis and sensing, for example, nondispersive infrared sensing technique. Both photoactive material engineering and nanophotonic filtering schemes have been explored to realize wavelength-selective photodetection, while most devices have a responsive bandwidth larger than 2% of the operating wavelength, limiting sensing performance. Near-infrared photodetection with a bandwidth of less than 0.2% of the operating wavelength was demonstrated experimentally in Au/Si Schottky nanojunctions. A minimum linewidth of photoelectric response down to 2.6 nm was obtained at a wavelength of 1550 nm by carefully tailing the absorptive and radiative loss in the nanostructures. Multiple functions were achieved on chip with the corrugated Au film, including narrowband resonance, light harvesting for sensing and photodetection, and electrodes for hot electron emission. Benefiting from such a unity integration with in situ photoelectric conversion of the optical sensing signal and the ultranarrowband resonance, self-contained on-chip biosensing via simple intensity interrogation was demonstrated with a limit of detection down to 0.0047% in concentration for glucose solution and 150 ng / mL for rabbit IgG. Promising potential of this technique is expected for the applications in on-site sensing, spectroscopy, spectral imaging, etc.

硫脲是一种含氮量高、 毒性较大的潜在蛋白掺假化合物, 常规的实验室检测方法过程复杂、 效率低, 无法满足口岸对大批次散装奶粉样本质量快速筛查的需求。 为解决口岸抽样监管缺乏快速实时评价方法的难题, 利用自主搭建的便携式点扫描拉曼高光谱成像系统, 开发了一种简单高效的奶粉中硫脲现场可视化快速检测方法, 确保散装奶粉在进出口环节的精准监管。 研究以不同添加浓度(0.005%~2.000%)的硫脲奶粉混合物为样本, 分别用Whittaker平滑方法和自适应迭代重加权惩罚最小二乘算法(airPLS)消除光谱数据的背景随机噪音信号和荧光背景干扰, 峰值识别后对硫脲特征位移处的单波段数据进行二值化处理, 得到混合样本感兴趣区域的二值热图, 通过二值图中硫脲像素点的有无和坐标, 对奶粉中的硫脲进行定性判别和定位分析。 进一步分析得感兴趣区域内硫脲像素点数目与添加浓度的关系, 结果表明随着添加浓度的增加, 硫脲像素点数目呈线性增长趋势, 其中线性拟合的决定系数(R²)为0.991 3, 硫脲的最低检出浓度为0.05%。 在0.25%, 0.60%, 1.20%和1.50%的添加水平下, 利用像素点数目和线性拟合关系预测奶粉中硫脲的浓度, 结果显示预测浓度的相对误差范围为-9.41%~4.01%, 相对标准偏差小于7%。 该点扫描拉曼高光谱成像系统能在10 min内完成单个样本的检测, 结合软件控制系统, 实时对奶粉中的硫脲颗粒进行定性、 定量和污染分布分析, 方法简单高效、 准确性好、 灵敏度高、 稳定性强, 为口岸现场对散装奶粉中硫脲掺假物的实时快速检测提供了技术监管手段, 能显著提升口岸现场散装样本的监管环节质量评价的精准性, 为进口奶粉快速通关提供技术保障。

Epsilon-near-zero (ENZ) modes have attracted extensive interests due to its ultrasmall mode volume resulting in extremely strong light-matter interaction (LMI) for active optoelectronic devices. The ENZ modes can be electrically toggled between on and off states with a classic metal-insulator-semiconductor (MIS) configuration and therefore allow access to electro-absorption (E-A) modulation. Relying on the quantum confinement of charge-carriers in the doped semiconductor, the fundamental limitation of achieving high modulation efficiency with MIS junction is that only a nanometer-thin ENZ confinement layer can contribute to the strength of E-A. Further, for the ENZ based spatial light modulation, the requirement of resonant coupling inevitably leads to small absolute modulation depth and limited spectral bandwidth as restricted by the properties of the plasmonic or high-Q resonance systems. In this paper, we proposed and demonstrated a dual-ENZ mode scheme for spatial light modulation with a TCOs/dielectric/silicon nanotrench configuration for the first time. Such a SIS junction can build up two distinct ENZ layers arising from the induced charge-carriers of opposite polarities adjacent to both faces of the dielectric layer. The non-resonant and low-loss deep nanotrench framework allows the free space light to be modulated efficiently via interaction of dual ENZ modes in an elongated manner. Our theoretical and experimental studies reveal that the dual ENZ mode scheme in the SIS configuration leverages the large modulation depth, extended spectral bandwidth together with high speed switching, thus holding great promise for achieving electrically addressed spatial light modulation in near- to mid-infrared regions. Epsilon-near-zero (ENZ) modes have attracted extensive interests due to its ultrasmall mode volume resulting in extremely strong light-matter interaction (LMI) for active optoelectronic devices. The ENZ modes can be electrically toggled between on and off states with a classic metal-insulator-semiconductor (MIS) configuration and therefore allow access to electro-absorption (E-A) modulation. Relying on the quantum confinement of charge-carriers in the doped semiconductor, the fundamental limitation of achieving high modulation efficiency with MIS junction is that only a nanometer-thin ENZ confinement layer can contribute to the strength of E-A. Further, for the ENZ based spatial light modulation, the requirement of resonant coupling inevitably leads to small absolute modulation depth and limited spectral bandwidth as restricted by the properties of the plasmonic or high-Q resonance systems. In this paper, we proposed and demonstrated a dual-ENZ mode scheme for spatial light modulation with a TCOs/dielectric/silicon nanotrench configuration for the first time. Such a SIS junction can build up two distinct ENZ layers arising from the induced charge-carriers of opposite polarities adjacent to both faces of the dielectric layer. The non-resonant and low-loss deep nanotrench framework allows the free space light to be modulated efficiently via interaction of dual ENZ modes in an elongated manner. Our theoretical and experimental studies reveal that the dual ENZ mode scheme in the SIS configuration leverages the large modulation depth, extended spectral bandwidth together with high speed switching, thus holding great promise for achieving electrically addressed spatial light modulation in near- to mid-infrared regions.

光学传感检测技术因具有精度高、低延时和可成像等优势而得到广泛应用。随着大数据和物联网等信息技术的迅速发展，对检测平台小型化和便携性的需求日益迫切。为了克服现有技术对大型专用设备的依赖，提高对现场快检、轻载荷平台等应用场景的适用性，近年来，基于微纳光学的片上集成光学传感检测技术受到了极大关注。通过集成光源、光学传感单元与光电探测单元、以及发展片上光色散等技术，可以有效地实现光学传感信号提取和光电信号转换的片上集成，从而实现系统的微型化和多功能集成。文中介绍了相关技术原理和技术发展现状，分析了现有技术的优缺点，讨论并总结了未来的发展方向和应用前景。