Regensburg 2010 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 10: Measuring Devices, Cryotechnique: Poster Session
TT 10.1: Poster
Montag, 22. März 2010, 14:00–18:00, Poster A
Broadband cw THz spectroscopy at low temperatures and high magnetic fields — •A. Janssen1, K. Thirunavukkuarasu1, H. Schmitz1, A. Roggenbuck1,2, A. Deninger2, I. Cámara Mayorga3, J. Hemberger1, R. Güsten3, and M. Grüninger1 — 1II. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, D-50937 Köln, Germany — 2TOPTICA Photonics AG, Lochhamer Schlag 19, D-82166 Gräfelfing, Germany — 3Max-Planck-Institute for Radio Astronomy, Auf dem Hügel 69, D-53121 Bonn, Germany
THz spectroscopy has been of great interest lately as it reveals the low-energy electronic phenomena in several materials like high-Tc superconductors, heavy fermion compounds and more recently multiferroic materials. While in particular time-domain THz-spectroscopy meanwhile has become a common tool, we use an optical homodyne method to generate a continuous-wave (cw) THz-Signal: A photomixer is illuminated by the light of two tunable DFB IR-lasers with adjacent frequencies and emits an electromagnetic wave through a silicon lens with the difference frequency in the THz-frequency range. A wide bandwidth, high spectral resolution and frequency stability are the benefits of this technique. For investigations at low temperatures and high magnetic fields, an integrated photomixer face-to-face assembly was set up circumventing the need of intensity diminishing optical components as lenses, mirrors, or windows. We will present the development and testing of a fiber-based cw broadband THz spectrometer in the frequency range of 60 GHz to 1.8 THz for the use within conventional 4He magneto-cryostat systems.