Tunable subwavelength focusing with dispersion-engineered metamaterials in the terahertz regime.
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.
Lee
Jinho
J
School of Mechanical Engineering, Yonsei University, 262 Seongsanno, Seodaemun-gu, Seoul 120-749, South Korea.
Lee
Kwangchil
K
Park
Haesung
H
Kang
Gumin
G
Yu
Dai-Hyuk
DH
Kim
Kyoungsik
K
D004738:Engineering / Q000379:methods*; D007909:Lenses; D012542:Scattering, Radiation; D013057:Spectrum Analysis; D013499:Surface Properties