Opt Lett. 2019 Jan 1;44(1):21-24. doi: 10.1364/OL.44.000021.
We demonstrate terahertz (THz) wave near-field imaging with a spatial resolution of ∼4.5 μm using single-pixel compressive sensing enabled by femtosecond-laser (fs-laser) driven vanadium dioxide (VO)-based spatial light modulator. By fs-laser patterning a 180 nm thick VO nanofilm with a digital micromirror device, we spatially encode the near-field THz evanescent waves. With single-pixel Hadamard detection of the evanescent waves, we reconstructed the THz wave near-field image of an object from a serial of encoded sequential measurements, yielding improved signal-to-noise ratio by one order of magnitude over a raster-scanning technique. Further, we demonstrate that the acquisition time was compressed by a factor of over four with 90% fidelity using a total variation minimization algorithm. The proposed THz wave near-field imaging technique inspires new and challenging applications such as cellular imaging.
我们展示了一种基于飞秒激光（fs 激光）驱动的基于二氧化钒（VO）的空间光调制器的单像素压缩感知技术，实现了空间分辨率约为 4.5 μm 的太赫兹（THz）波近场成像。通过数字微镜器件对 180nm 厚的 VO 纳米薄膜进行 fs 激光图案化，我们对近场太赫兹消逝波进行了空间编码。通过对消逝波进行单像素的哈达玛检测，我们从一系列编码的顺序测量中重建了物体的太赫兹近场图像，与光栅扫描技术相比，信噪比提高了一个数量级。此外，我们还证明，通过全变差最小化算法，在保持 90%保真度的情况下，采集时间被压缩了四倍以上。所提出的太赫兹波近场成像技术为细胞成像等新的具有挑战性的应用提供了启示。
