Study of a Composite Consisting of Metal Nanoparticles in a Dielectric Matrix and Multilayer Bandpass Filters Based on It

The frequency and concentration dependences of the effective complex permittivity of a composite consisting of silver nanoparticles in a polystyrene dielectric matrix have been investigated. It has been found that, with an increase in the volume concentration of particles in the composite to ~33%, the real part of its permittivity increases from 2.6 to ~10 3 , while the loss tangent remains no higher than 10 –2 up to a frequency of 1 THz. We show the possibility of designing bandpass filters based on composite layered structures, which can be tuned by selecting the particle concentration in the quarter-wavelength layers of the mirrors that ensure the optimal interaction of half-wavelength resonators with each other and the outer resonators with free space. The high contrast between the matrix and the composite permittivities makes it possible to create mirrors with a required reflectivity using a minimum number of layers.