A simple subwavelength focusing system formed by a straight or bent multimode waveguide is investigated numerically. The simulation results indicate that an appropriately designed multimode waveguide can focus the outgoing waves of a point source and form an image with a full width at half-maximum of less than half a wavelength in the near-field area at the other side of the waveguide. The physical mechanism of the subwavelength focusing for this imaging system is explained.
© 2004 Optical Society of America
Xianyu Ao and Sailing He, "Subwavelength focusing and imaging by a multimode optical waveguide," Opt. Lett. 29, 2864-2866 (2004)