A method to widen the scattering bandwidth of closed cylindrical active coated nano particles

Plane wave scattering from two closely spaced, closed cylindrical active coated nano particles (CNPs), which have slightly different resonance frequencies, is studied numerically. Although the distance between them is only 0.4λ, the scattering cross-section(SCS) background value of this two-CNP system is increased 5dB when r2 = 15.1 nm and the 3dB SCS bandwidth is 599.95THz-600.1THz, which is a substantially wider working bandwidth near the SCS peak than the one associated with either single CNP, i.e. 600.01THz-600.1THz.