Chinese Optics Letters, Vol. 13, Issue 9, 093001 (2015)
Origin of potential errors in the quantitative determination of terahertz optical properties in time-domain terahertz spectroscopy
Qijun Liang1, Gregor Klatt2, Nico Krauß1, Oleksii Kukharenko3, and Thomas Dekorsy1,*
- 1Department of Physics and Center for Applied Photonics, University of Konstanz, 78464 Konstanz, Germany
- 2Laser Quantum GmbH, 78464 Konstanz, Germany
- 3Faculty of Physics, National Taras Shevchenko University of Kyiv, 01601 Kyiv, Ukraine
We demonstrate theoretically and experimentally how changes of a terahertz (THz) beam induced by the sample affect the accuracy of the determination of THz dielectric properties in THz time-domain transmission spectroscopy (TDTS). We apply a Gaussian beam and the ABCD matrix formalism to describe the propagation of the THz beam in a focused beam setup. The insertion of the sample induces a focus displacement which is absent in the reference measurement without a sample. We show how the focus displacement can be corrected. The THz optical properties after focus displacement correction reported in this Letter are in quantitative agreement with those obtained using collimated beam THz–TDTS in previous work.