Near-and far-field simulations of 2D particles with photonic structure

We present a numerical computation scheme for calculation of the reflected and transmitted near- and farfields arising from the interaction of 2D cylindrical shaped particles with photonic structures. The photonic structures are illuminated with either planar or Gaussian incident fields. The interaction between the cylindrical particle and the photonic structure is generally too complex to be handled analytically, so we will use the semianalytical Fourier Modal Method (FMM) to calculate the near- and far-fields. The Gaussian field is written as a sum of plane waves with varying amplitudes. We present a very general method for obtaining the plane wave amplitudes by combining the angular spectrum theory, Parseval's theorem and Shannon's sampling theorem. We demonstrate the use of this method in our rigorous calculation of reflected and transmitted near- and far-fields of single cylindrical particle located in the vicinity of a periodic photonic structure or a planar silicon surface. The examples demonstrate that the method may be applied to particle counting.