Abstract-Efficient coupling of double-metal terahertz quantum cascade lasers to flexible dielectric-lined hollow metallic waveguides

R. Wallis, R. Degl’Iinnocenti, D. S. Jessop, Y. Ren, A. Klimont, Y. D. Shah, O. Mitrofanov, C. M. Bledt, J. E. Melzer, J. A. Harrington, H. E. Beere, and D. A. Ritchie
https://www.osapublishing.org/oe/abstract.cfm?uri=oe-23-20-26276

The growth in terahertz frequency applications utilising the quantum cascade laser is hampered by a lack of targeted power delivery solutions over large distances (>100 mm). Here we demonstrate the efficient coupling of double-metal quantum cascade lasers into flexible polystyrene lined hollow metallic waveguides via the use of a hollow copper waveguide integrated into the laser mounting block. Our approach exhibits low divergence, Gaussian-like emission, which is robust to misalignment error, at distances > 550 mm, with a coupling efficiency from the hollow copper waveguide into the flexible waveguide > 90%. We also demonstrate the ability to nitrogen purge the flexible waveguide, increasing the power transmission by up to 20% at 2.85 THz, which paves the way for future fibre based terahertz sensing and spectroscopy applications.

© 2015 Optical Society of America

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