Increased detection sensitivity was achieved by adjusting the incident angle on periodic gold nanostructures that induced a resonant coupling between surface and substrate surface plasmon modes. For 500 nm-period gold nanoslits, a small incident angle, 7°, resulted in 2.64 times narrower linewidth and a 1.8 times increase in the figure of merit as compared to normal incidence. Furthermore, the intensity sensitivity was increased 4.5 times due to the change in the resonant coupling and redshift of the surface plasmon mode.
© 2013 Optical Society of America
Original Manuscript: August 26, 2013
Revised Manuscript: October 15, 2013
Manuscript Accepted: October 15, 2013
Published: November 20, 2013
Wan-Shao Tsai, Kuang-Li Lee, Ming-Yang Pan, and Pei-Kuen Wei, "Increased detection sensitivity of surface plasmon sensors using oblique induced resonant coupling," Opt. Lett. 38, 4962-4965 (2013)