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Optical components for the THz-field

Photo by Prof. Martin Koch

Figure 1: A THz waveplate of paper

Since Thz-waves may be considered long. wave light many concepts for components can be conveyed from optics to the THz-field.

In recent years the Terahertz research group of the semiconductor photonics group developed a variety of optic components for THz-waves, manufacturing costs always considered. These components could become key-components for terahertz communication technologies.

To name are:

Dielectric mirrors and filters (also switchable)

N. Krumbholz et al, Omnidirectional terahertz mirrors: a key element for future THz communication systems, Appl. Phys. Lett. 88, 202905 (2006) [DOI].

F. Rutz et al., Ceramic dielectric mirrors for the terahertz range, Appl. Opt. 45, 8070 (2006)  [DOI].

I.A. Ibraheem et al., Low-Dispersive Dielectric Mirrors for Future Wireless Terahertz Communication Systems, IEEE Microwave, and Wireless Components Letters, 18, 67 (2008)  [DOI].

R. Wilk et al, Liquid crystal based electrically switchable Bragg structure for THz waves, Opt. Exp. 17, 7377 (2009)  [DOI].

C. Jansen et al, Mechanically Flexible Polymeric Compound 1D Photonic Crystals for Terahertz Frequencies, Appl. Phys. Lett. 96, 111108 (2010)  [DOI].

First THz lens with a variable focal length

B. Scherger, C. Jördens, and M.Koch, Variable-focus terahertz lens, Opt. Exp.19, 4528 (2011) [DOI].

THz lenses and diffraction grating of polymer-powder or polymeric compounds

B. Scherger, M. Scheller, C. Jansen, M. Koch, and K. Wiesauer,  THz lenses made by compression molding of micro-powders, Appl. Opt. 50, 2256 (2011) [DOI].

B. Scherger, S. Wietzke, M. Scheller, N. Vieweg, M. Wichmann, M. Koch, and K. Wiesauer,  Characterization of Micro-Powders for the Fabrication of Compression Molded THz Lenses, J. Infrared Milli Terahz Waves, 32, 943 (2011) [DOI].

B. Scherger, N. Born, C. Jansen, S. Schumann, M. Koch, and K. Wiesauer,  Compression Molded Terahertz Transmission Blaze-Grating, IEEE Terahertz Sci. and Technol. 2, 556 (2012) [DOI].

S.F. Busch, N. Born, M. Koch, B. Fischer,  Terahertz Reflection Gratings Made by Room-Temperature High-Pressure Molding, J. Infrared Milli Terahz Waves, 34, 413 (2013) [DOI].

M. Wichmann, A.S. Mondo, N. Kocic, S. Lippert, T. Probst, M. Schwerdtfeger, S. Schumann,  T. Hochrein, P. Heidemeyer, M. Bastian, G. Bastian and M. Koch,  Terahertz Plastic Compound Lenses, Appl. Opt. 52, 4186 (2013) [DOI].

Frequency selective surfaces as a filter and sensor technology

C. Jansen, I.A.I. Al-Naib, N. Born, and M. Koch,  Terahertz metasurfaces with high Q-factors, Appl. Phys. Lett, 98, 051109 (2011) [DOI].

I. A. I. Al-Naib, C. Jansen, N. Born,   and M. Koch,  Polarization and Angle Independent Terahertz Metamaterials with High Q-factors, Appl. Phys. Lett. 98, 091107 (2011) [DOI].

N. Born, M. Reuter, M. Koch, and M. Scheller,  High-Q terahertz bandpass filters based on coherently interfering metasurface reflections, Optics Letters 38, 908 (2013) [DOI].

N. Born, I. Al-Naib, C. Jansen, T. Ozaki, R. Morandotti, and M. Koch,  Excitation of multiple trapped-eigenmodes in terahertz metamolecule lattices, Appl. Phys. Lett. 104, 101107 (2014) [DOI].

A switchable grating to focus and pivot THz bundle of rays

Y. Monnai, K. Altmann, C. Jansen, H. Hillmer, M. Koch, and H. Shinoda, Terahertz beam steering and variable focusing using programmable diffraction gratings, Opt. Exp. 21, 2347 (2013) [DOI].

A very good valued delay line for THz pulses

T. Probst, A. Rehn, S.F. Busch, S. Chatterjee, M. Koch, and M. Scheller,  Cost-efficient delay generator for fast terahertz imaging, Opt. Lett. 39, 4863 (2014) [DOI].

THz-optics from the 3D-printer

M. Weidenbach, D. Jahn, A. Rehn, S.F. Busch, F. Beltrán-Mejía, J.C. Balzer, and M. Koch, 3D printed dielectric rectangular waveguides, splitters, and couplers for 120 GHz, Opt. Exp. 24, 28968 (2016) [DOI].

The use of a 3D-Printer to create Thz-optics allows great flexibility and scope for design. At the moment we focus on exploring the great variety of opportunities this procedure provides.

Finally, a nice example of recent years be mentioned: the THz waveplate of paper.

B. Scherger, M. Scheller, N. Vieweg, S.T. Cundiff, and M. Koch,  Paper terahertz wave plate , Optics Express 19, 24884 (2011) [DOI]