We designed and implemented a gradient index metasurface for in-plane focusing of confined terahertz (THz) surface waves. We measured the spatial propagation of the surface waves by two-dimensional mapping of the complex electric field using a THz near-field spectroscope. The surface waves were focused to a diameter of 500 μm after a focal length of approximately 2 mm. In the focus, we measured a field amplitude enhancement of a factor of 3.
© 2013 Optical Society of America
Original Manuscript: March 25, 2013
Manuscript Accepted: May 21, 2013
Published: June 14, 2013
Martin F. Volk, Benjamin Reinhard, Jens Neu, René Beigang, and Marco Rahm, "In-plane focusing of terahertz surface waves on a gradient index metamaterial film," Opt. Lett. 38, 2156-2158 (2013)