Optical nonlinear enhancement from binary optimization of plasmonic nano-bi-domes

Here, we theoretically suggest the possibility of optical nonlinear enhancement by employing the binary optimization of plasmonic nano-bi-domes. Since the nonlinear coefficient depends strongly on the number of plasmonic nanoparticles and the nanoparticles location, binary particle swarm optimization (BPSO) algorithm is proposed to design an optimized array of the plasmonic nano-bi-domes in order to achieve the maximum nonlinear coefficient in the optical frequency. In BPSO, a swarm consists of a matrix with binary entries, control the presence (‘1’) or the absence (‘0’) of nano-bi-domes in the array. It is shown that the interaction between six nano-bi-domes leads to a very strong amplification of the Electro Magnetic (EM) fields inside and in the near-field range outside the particles. Correspondingly, such systems exhibit strong resonance peaks in the nonlinear coefficient spectrum.