We develop a terahertz lens with both subwavelength resolution and tunable far-field focal length by extending the surface plasmon (SP) diffraction theory into spoof SPs of slit-groove-structure terahertz metamaterials. The dispersion properties of terahertz groove structures are engineered in the curved depth profile to produce a directional beaming feature and mimic SPs at the same time. The finite-difference time-domain simulation results confirm that the far-field focal position can be tuned by controlling the curvature of the relative electric field phase distribution profile on the output surface.
© 2010 Optical Society of America
Original Manuscript: February 25, 2010
Revised Manuscript: June 3, 2010
Manuscript Accepted: June 8, 2010
Published: June 29, 2010
Vol. 5, Iss. 11 Virtual Journal for Biomedical Optics
Jinho Lee, Kwangchil Lee, Haesung Park, Gumin Kang, Dai-Hyuk Yu, and Kyoungsik Kim, "Tunable subwavelength focusing with dispersion-engineered metamaterials in the terahertz regime," Opt. Lett. 35, 2254-2256 (2010)