Chinese University of Hong Kong, Electronic Engineering, Hong Kong SAR, China.
State Key Laboratory of Power Transmission Equipment & System Security and New Technology, School of Electrical Engineering, Chongqing University, Chongqing, 400044, China.
Nat Commun. 2020 May 21;11(1):2535. doi: 10.1038/s41467-020-16370-x.
Terahertz (THz) radiation is poised to have an essential role in many imaging applications, from industrial inspections to medical diagnosis. However, commercialization is prevented by impractical and expensive THz instrumentation. Single-pixel cameras have emerged as alternatives to multi-pixel cameras due to reduced costs and superior durability. Here, by optimizing the modulation geometry and post-processing algorithms, we demonstrate the acquisition of a THz-video (32 × 32 pixels at 6 frames-per-second), shown in real-time, using a single-pixel fiber-coupled photoconductive THz detector. A laser diode with a digital micromirror device shining visible light onto silicon acts as the spatial THz modulator. We mathematically account for the temporal response of the system, reduce noise with a lock-in free carrier-wave modulation and realize quick, noise-robust image undersampling. Since our modifications do not impose intricate manufacturing, require long post-processing, nor sacrifice the time-resolving capabilities of THz-spectrometers, their greatest asset, this work has the potential to serve as a foundation for all future single-pixel THz imaging systems.
太赫兹（THz）辐射有望在许多成像应用中发挥重要作用，从工业检查到医学诊断。然而，由于太赫兹仪器不切实际且昂贵，商业化受到阻碍。由于成本降低和耐用性提高，单像素相机已成为多像素相机的替代品。在这里，通过优化调制几何形状和后处理算法，我们使用单像素光纤耦合光电导太赫兹探测器实时演示了太赫兹视频（32×32 像素，每秒 6 帧）的采集。一个带有数字微镜器件的激光二极管将可见光照射到硅上，充当空间太赫兹调制器。我们从数学上考虑了系统的时间响应，通过无锁定载波调制降低了噪声，并实现了快速、抗噪的图像欠采样。由于我们的修改没有采用复杂的制造工艺，不需要长时间的后处理，也没有牺牲太赫兹光谱仪的时间分辨率能力，这是它们最大的优势，因此这项工作有可能成为所有未来单像素太赫兹成像系统的基础。
