Deterministic aperiodic photonic crystal with a 2D array of metallic nanoparticles as polarization-sensitive dichroic filter

Abstract

We demonstrate the possibility of using a two-dimensional array of spheroidal metallic nanoparticles embedded in a one-dimensional photonic crystal to obtain a narrow-bandpass, polarization-sensitive dichroic filter operating in the near-UV and visible domains. The optical anisotropy of the array of identically oriented nanoparticles results in two spectrally distinct plasmon resonances independently excited for two mutually orthogonal linear polarization states of light, which ensures polarization and spectral selectivity of the composite structure. The narrow transmission bands of the filter are defect modes due to a layer located at the center of the structure and hosting the nanoparticle array. In order to suppress these transmission windows, it is essential that the defect modes closely coincide with the plasmon resonances excited in the array. We show that the use of deterministic aperiodic distributed reflectors surrounding the defect layer makes it possible to adjust the spectral positions of two defect modes in two separate bandgaps in order to achieve such a coincidence. Among the various parameters governing the precise position of transmittivity windows of the filter, we establish the strong influence of the thickness of the defect layer. We also show that a strong localization of the optical field in the plane of the nanoparticle array is essential to enhance the efficiency of plasmonic excitation and obtain the desired control of the defect modes. Our study opens up possibilities for the further development of polarization-controlled nanophotonic devices.