Nanostructures have a variety of applications in sensors, spectroscopic and optoelectronic devices. Metamaterials have developed into one of the most focused research fields in nano-optics and nanomaterials and attract extensive research interests. This is not only due to the rich physics in this kind of materials, but also because they are closely related to some new techniques in the control of terahertz radiation, solar power management, optical cloaking, antenna systems, etc.