Abstract

We show that the lowest mode waveguide cutoff in cylindrical holes in real metals controls the transmission profile in line arrays of subwavelength round holes as a function of the array pitch. This behavior is in sharp contrast to the transmission profile in arrays of subwavelength slits where the lowest waveguide mode exhibits no cutoff. The transmission profile in both slits and holes is determined by interference between surface waves and the incident standing wave. We show through full 3-D, FDTD simulations that the phase of the interference pattern is a sensitive function of the position of the lowest-order waveguide mode, above or below cutoff.

© 2010 Optical Society of America