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

Si-Chao Chen, Liang-Hui Du, Kun Meng, Jiang Li, Zhao-Hui Zhai, Qi-Wu Shi, Ze-Ren Li, and Li-Guo Zhu

https://www.osapublishing.org/ol/abstract.cfm?uri=ol-44-1-21

We demonstrate terahertz (THz) wave near-field imaging with a spatial resolution of ∼4.5  μm$\sim 4.5\mathrm{\mu m}$using single-pixel compressive sensing enabled by femtosecond-laser (𝑓𝑠$fs$-laser) driven vanadium dioxide (VO2${\mathrm{VO}}_2$)-based spatial light modulator. By 𝑓𝑠$fs$-laser patterning a 180 nm thick VO2${\mathrm{VO}}_2$ 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.

© 2018 Optical Society of America