Abstract

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

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