ABSTRACT
Metamaterials are artificial materials that are known to produce extraordinary electromagnetic responses due to their constituent artificially-engineered micro-or nanostructures with dimensions smaller than that of the wavelength of light. The Split Ring Resonator (SRR) is one such nanostructure that forms the basic unit of a metamaterial. Since the dimensions of the SRRs are required to be smaller than the resonance wavelength, their fabrication becomes critical when a response is required at near infrared and optical wavelengths. In this chapter, the various properties of nanoscale
SRRs are studied that resonate in the infrared and visible spectrum. The SRRs discussed in this chapter are made of aluminium (Al) and gold (Au) and have been fabricated on silicon and silica substrates using electron beam lithography (EBL) nanofabrication techniques. It is shown that, by using aluminium-based SRRs instead of gold ones, the magnetic resonance of SRRs can be shifted well into the visible spectrum. Finally, it is shown that, by adding asymmetry to similar sized geometrical structures such as doubly-split SRRs, it is possible to produce a steeper resonance response, thereby increasing the quality factor of the SRRs. This steep response of asymmetric split ring resonators (A-SRRs) is utilized for the optical detection of very thin films of organic compounds.
