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Surface
plasmon polaritons (SPP) play a key role in many research applications
and
devices [1]. To couple SPP from a free-space wave, by matching their
wave
vectors (momentum), a Prism or a periodic grating are frequently used.
However,
by these methods, only a single wavelength at a specific angle can by
coupled
into a single SPP.
We show that quasiperiodic grating
enable the
coupling of light at multiple wavelengths and angles. The quasiperiodic
grating
was designed in a systematic manner using the dual-grid method (DGM)
[2]. The
robust DGM algorithm allows us to control the coupling strength and
grating
dimensions for almost any arbitrary set of wave vector mismatches. We
verified
the method experimentally by efficiently coupling light into a surface
plasmon
from several different illumination angles using a single quasiperiodic
grating
[3]. This SPP coupling technique can be used for a wide range of
applications
where multiple coupling conditions are required, such as biochemical
SPP
sensors, nonlinear optics, and other SPP subwavelength optical devices.
Written by: Ido Dolev
References:
[1]
S. A. Maier, Plasmonics: Fundamentals and Applications (Springer, 2007).
[2] R. Lifshitz, A. Arie,
and A. Bahabad, Phys.
Rev. Lett. 95, 133901 (2005).
[3]
I. Dolev, M. Volodarsky, G. Porat and A. Arie, Multiple coupling of
surface
plasmons
in quasiperiodic gratings, Optics
Letters, 36, 1584-1586, (2011).
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