Abstract: Dynamically reconfigurable terahertz metamaterial through photo-doped semiconductor

http://apl.aip.org/resource/1/applab/v99/i23/p231101_s1?isAuthorized=no

Dibakar Roy Chowdhury¹, Ranjan Singh¹, John F. O’Hara^1,2, Hou-Tong Chen¹, Antoinette J. Taylor¹, and Abul K. Azad¹

¹Center for Integrated Nanotechnologies, Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
²School of Electrical and Computer Engineering, Oklahoma State University, Stillwater, Oklahoma 74078, USA

We demonstrate reconfigurable terahertz metamaterial (MM) in which constituent resonators can be switched from split-ring resonators (SRRs) to closed-ring resonators via optical excitation of silicon islands strategically placed in the split gap. Both the fundamental and the third-order resonance modes experience monotonic damping due to increasing conductive losses in the photo-doped silicon region. More importantly, increasing the optical fluence (>200 μJ/cm²) results in the excitation of the second-order resonance mode, which is otherwise forbidden in a split-ring resonator for the incidence polarization in our experiments. Such dynamical control of metamaterial resonances could be implemented in active terahertz devices to achieve additional functionalities.

© 2011 American Institute of Physics