Compressed sensing pulse-echo mode terahertz reflectance tomography.

We demonstrate pulse-echo mode terahertz (THz) reflectance tomography, where scattered THz waveforms are measured using a high-resolution asynchronous-optical-sampling THz time domain spectroscopy (AOS THz-TDS) technique, and 3-D tomographic reconstruction is accomplished using a compressed sensing approach. One of the main advantages of the proposed system is a significant reduction of acquisition time without sacrificing the reconstruction quality, thanks to the sufficient incoherency in the pulse-echo mode-sensing matrix and the fast sampling scheme in AOS THz-TDS.