We have demonstrated a surface plasmon polariton mediated optical Moiré effect by inserting a silver slab between two subwavelength gratings. Enhancement of the evanescent fields by the surface plasmon excitations on the silver slab leads to a remarkable contrast improvement in the Moiré fringes from two subwavelength gratings. Numerical calculations, which agree very well with the experimental observation of evanescent-wave Moiré fringes, elucidate the crucial role of the surface plasmon polaritons. The near-field Moiré effect has potential applications to extend the existing Moiré techniques to subwavelength characterization of nanostructures.
© 2007 Optical Society of America
Instrumentation, Measurement, and Metrology
Original Manuscript: October 9, 2006
Revised Manuscript: November 20, 2006
Manuscript Accepted: December 18, 2006
Published: February 15, 2007
Zhaowei Liu, Stéphane Durant, Hyesog Lee, Yi Xiong, Yuri Pikus, Cheng Sun, and Xiang Zhang, "Near-field Moiré effect mediated by surface plasmon polariton excitation," Opt. Lett. 32, 629-631 (2007)