Optical Activity Effect on Planar Chiral Metamaterials

Metamaterial is an artificial material which has a negative refractive index. Both of permitivitty and permeability have a negative value to possess negative refraction. The breakthrough of metamaterial development was present as the invention of planar chiral metamaterials. This research was focussed on the development of a new design of planar chiral metamaterial with different depth. The developed metamaterial design was analyzed by chirality analysis in relation to the optical activity characteristics.

The planar chiral metamaterial development was following a design, a structure examination, and a fabrication process using a focused ion beam system. Chirality characterization were measured using a femtosecond Ti:Sapphire pumped terahertz emission spectroscopy system. THz signal was occurred due to the optical rectification process as a result of an intense femtosecond laser pulses radiation on planar chiral metamaterial sample. The samples were capable to generate a THz emission over a frequency range of 0 − 2.24 THz, while the THz signal was measured as ∼5 ps. The effect of optical activity was able to rotate the polarization plane on a frequency range of 0 – 1.4 THz for both of the clockwise and the counter-clockwise samples. The maximum polarization plane rotation were +13° and −18° at a frequency 1.35 THz. It can be concluded that the new design planar chiral metamaterial with different depth has been successfully obtained with its elliptic polarized THz emission characteristic. (paper)