Plasmonic Enhanced Chiral Metamaterials

F. Alali, Y.H. Kim, E.P. Furlani
University at Buffalo, US

Keywords: chiral materials, optical activity, plasmonics, metamaterials, negative index materials


Metamaterials are artificial materials that are engineered to produce various interesting phenomena such as negative refractivity and sub-diffraction-limit imaging. The majority of metamaterials for THz applications have been fabricated using “top-down” techniques. These methods tend to be limited to the fabrication of 2D planar materials on rigid substrates at low throughput and with high-cost. Here, we discuss a fundamentally different approach to metamaterials that involves the use of chiral polymers. The chirality of a material can be characterized in terms of a chirality parameter. If it is sufficiently large, a bulk negative index can be realized for one of the circular polarization states of the incident field. We present a bottom-up approach for realizing flexible polymer-based metamaterials with enhanced chirality. This is achieved by introducing metallic nanoparticles into a chiral polymer with a plasmon resonance that is tuned to the molecular chiral response of the media and then further patterning the nanocomposite into chiral shapes to obtain a chiral response both at the molecular level and geometrically at a length scale on the order of the wavelength of the incident field. We report on progress towards this end by demonstrating laser-based patterning of novel planar chiral metamaterials.