Terahertz wave near-field compressive imaging with a spatial resolution of over λ/100

• Published in: Optics letters Vol. 44; no. 1; p. 21
• Main Authors: Chen, Si-Chao, Du, Liang-Hui, Meng, Kun, Li, Jiang, Zhai, Zhao-Hui, Shi, Qi-Wu, Li, Ze-Ren, Zhu, Li-Guo
• Format: Journal Article
• Language: English
• Published: United States 01.01.2019
• ISSN: 1539-4794
• 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.