152937.fig.007a
(a)
152937.fig.007b
(b)
152937.fig.007c
(c)
152937.fig.007d
(d)
Figure 7: Front view of the metal surface. The illumination is incident from the back of the screen. (a) The screen containing a slit-cubic curve recorded on a thin metal film. (b) The surface plasmon diffraction field and its singular region. (c) Transmittance containing a parabolic curve and (d) singularity associated with this transmittance.