title: Two-dimensional tomographic terahertz imaging by homodyne self-mixing.
abstract: We realize a compact two-dimensional tomographic terahertz imaging experiment involving only one photoconductive antenna (PCA) simultaneously serving as a transmitter and receiver of the terahertz radiation. A hollow-core Teflon cylinder filled with α-Lactose monohydrate powder is studied at two terahertz frequencies, far away and at a specific absorption line of the powder. This sample is placed between the antenna and a chopper wheel, which serves as back reflector of the terahertz radiation into the PCA. Amplitude and phase information of the continuous-wave (CW) terahertz radiation are extracted from the measured homodyne self-mixing (HSM) signal after interaction with the cylinder. The influence of refraction is studied by modeling the set-up utilizing ZEMAX and is discussed by means of the measured 1D projections. The tomographic reconstruction by using the Simultaneous Algebraic Reconstruction Technique (SART) allows to identify both object geometry and α-Lactose filling.
authors.forename: Till
authors.initials: T
authors.lastname: Mohr
authors.forename: Stefan
authors.initials: S
authors.lastname: Breuer
authors.forename: G
authors.initials: G
authors.lastname: Giuliani
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Elsäßer