Terahertz properties of metal-dielectric composites

Contacts:

Maksim Zalkovskij, DTU Fotonik, 4525-6869 (mzal@fotonik.dtu.dk)

Andrei Lavrinenko, DTU Fotonik, 4525-6392 (alav@fotonik.dtu.dk)

Metal films or particles have been studied intensively in the recent decades in optics due to their unique photonic features. The optical properties of metal–dielectric structures (like a thin metal film on a dielectric substrate) are governed by surface plasmon resonances, which are the collective oscillations of conduction electrons in a metal structure under incident light. Plasmonic nanostructures act like nanoantennas, accumulating and building up electromagnetic energy in nanometer-scale. However, in the terahertz (THz) range (compare frequencies in optics – 100-1000·1012 Hz = 100-1000 THz and in the terahertz range – 0.1-10 THz) metals are too close in properties to the ideal perfect conductor to support such resonances. THz radiation has an enormous potential in broad range of fields as in biology, communication, security, chemistry and spectroscopy. So lacking of plasmonic structures in the THz physics is considered as one of top problems to be overcome. The current idea is to make a metal-dielectric composites by doping a dielectric or polymer matrix with metal nanoparticles to dilute otherwise too strong metal properties.

The project consists of two parts. In the first effective properties of such composites will be evaluated theoretically. In particularly, the task is to compute transmission and reflection spectra knowing the sizes and concentration of the metal particles. Also the concentration of metal particles will be estimated to obtain prescribed transmission properties. Then such composites will be fabricated by our partners in the Kiel University (Germany), who has the technology available.

The second part of the project is to characterize such composites in the THz lab and compare results with the theoretical predictions. Thus participants will get theoretical knowledge and characterization skills in plasmonics and experimental terahertz physics.