Tunable negative-index photonic crystals using colloidal magnetic fluids*
Geng Tao†, Wang Xin, Wang Yan, Dong Xiang-Mei
       
(a) Calculated effective indices of 2D PCs versus external magnetic field at f = 0.45 along the ΓM direction. The normalized average intensities of a point source with f = 0.45 located at 0.65 λ from the PC lens at (b) H = 150 Oe and (c) H = 250 Oe. In panels (b) and (c), the solid lines show the position of the PC lens. The z positions of the images are marked by the dashed lines. (d) The normalized average intensities along the x direction at the image plane at H = 150 Oe and H = 250 Oe. (e) The transmission of light from a point source with f = 0.45 through the PC lens as a function of external magnetic field.