Light focusing by the unique dielectric nano-waveguide array.

The light focusing by using dielectric nano-waveguides array with its length in micron is investigated via the finite-difference time domain (FDTD) method. Simulated results show that the focal length depends on the length and the total width of the arrays and can be altered from tens of micron to wavelength order. Both TM and TE mode incident light can be focused by the array. The wavelength-order focal length is achieved by employing the dielectric nano-waveguide array with variant separations. The unique focusing behavior is contributed to the radiation mode with longer decay length and the large evanescent field which appears in the nano-waveguide array. We believe this simulation results can be a promising guidance for the experiments.