Defect-assisted plasmonic crystal sensor.

We demonstrate enhanced sensitivity of a nanostructured plasmonic sensor that utilizes resonance in intentional structural defects within a plasmonic crystal. The measured sensitivity of the fabricated nanosensor is ~500 nm/RIU showing improvement over traditional nanohole array sensors. Furthermore, the defects provide an additional design parameter to increase sensitivity by engineering plasmon lifetime.

A periodically coupled plasmon nanostructure for refractive index sensing.

We present unique characteristics of subwavelength surface plasmon polaritons in a periodically coupled nanowell structure. The nanowell structure offers high quality internal surface plasmon resonance for sensing applications. Calculated FWHM of the transmission peak is 6 nm and the optical transmission is close to 100% at the resonant wavelength of 815.8 nm. The highly concentrated polaritons in the nanowell are sensitive to surface changes providing a sensitivity of 4800% RIU(-1) for optical sensing applications.