Plasmonic metamaterials for ultrasensitive refractive index sensing at near infrared

Abstract

We experimentally report a kind of plasmonic metamaterials for high sensitive refractive index sensing. The metamaterials are an X-shaped metal nanohole array fabricated by holographic lithography followed by electron-beam evaporation and lift-off procedure. Transmission spectrum measurements reveal that the localized surface plasmon resonance (LSPR) wavelength of such nanohole array shows ultrasensitive response to refractive index change in the surrounding medium. A sensitivity of 1398 nm per refractive index unit is achieved at near infrared. The high sensitivity is attributed to the well confined and greatly enhanced electric field created by LSPR as well as the increased spatial overlap between the localized electric field and the surrounding medium. The robust fabrication technique and high sensitivity provide the present plasmonic metamaterials great potentials for the development of chip-based high sensitive nanooptical biomedicine sensors and integrated devices.

H-Shape Plasmonic Metasurface as Refractive Index Sensor

“…4d, showing a maximum 700-nm shift for 25-nm channel width. This sensitivity is comparable to the reported sensitivity of X-shape structure [41]. The present results show a better sensitivity for the structure with smaller channel width.…”

“…Usually, for reproducible results, periodic structures are favored over irregular one. Using periodic plasmonic metasurface, typically, a linear shift of 1000 nm per RIU (Δλ/Δn) in the resonance transmission or reflection is reported [29,40,41]. In the channel-or slit-plasmonic metasurfaces, the resonance frequency is primarily determined by the capacitive coupling of the structures with the surrounding medium as has already been mentioned.…”

A multiplexed label free plasmonic nano-device for near infrared applications

“…The alternative way to excite SPR is the coupling via a diffraction grating matching the momentum difference between the plasmon and the light incident at a defined angle [18][19][20][21][22][23][24][25]. This method is usually considered less efficient and affected by disturbance from the medium, typically the flowing analyte solution, when light is impinging from-and/or passing through-the analysis cell [19].…”

Design and implementation of plasmonic metamaterials and devices

“…Even more recently these values were improved by a design of nanocross holes in metal, as shown in Fig. 4.1(e), achieving a sensitivity of 1400 nm/RIU [228].…”

“…The impressive possibility of detecting a single molecule of the analyte could be achievable. [224], (b) [225], (c) [226], (d) [227] and (e) [228].…”