One of the keys to understanding the extraordinary optical transmission in a subwavelength metal slit is in what field mode is excited. We find that, compared to the usual surface plasmon polariton (SPP), the wavelength of the excited mode is squeezed and will become smaller as the slit width does. This mode is called an in-slit SPP. We show how the wavelength of this mode can be solved by a formula and clearly analyze the physical reason for the wavelength squeeze. Furthermore, the similarities and differences of the wavelength squeeze between normal incidence and oblique incidence are pointed out.
© 2009 Optical Society of America
Optics at Surfaces
Original Manuscript: July 1, 2009
Revised Manuscript: October 27, 2009
Manuscript Accepted: November 5, 2009
Published: December 18, 2009
Chao Li, Yun-Song Zhou, Huai-Yu Wang, and Fu-He Wang, "Wavelength squeeze of surface plasmon polariton in a subwavelength metal slit," J. Opt. Soc. Am. B 27, 59-64 (2010)