We utilize three diffraction theories to investigate the focal-shift phenomena of plasmonic lenses. By taking the Fresnel number into account, a better accuracy in predicting the relative focal shift can be achieved for low-Fresnel-number systems. On the basis of this focal-shift effect, we present a method to realize an active plasmonic lens. Two-dimensional finite-difference time-domain simulation is performed to verify the method proposed.
© 2012 Optical Society of America
Optical Design and Fabrication
Original Manuscript: December 14, 2011
Revised Manuscript: January 16, 2012
Manuscript Accepted: February 15, 2012
Published: May 2, 2012
Yiting Yu and Hans Zappe, "Theory and implementation of focal shift of plasmonic lenses," Opt. Lett. 37, 1592-1594 (2012)