Full text loading...
(a)–(f) Schematic showing the process for fabricating gold coaxial rod-tube arrays. (g) and (h) SEM images of the final structure after polypyrrole and alumina removal. The average dimensions (and standard deviation, σ) of the structures in (h) are: 20 nm nanorod diameter (σ = 3 nm), 10 nm nanotube wall (σ = 1 nm), 7.5 nm cavity (σ = 1 nm), and 70 nm spacing (σ = 6 nm).
(a) Experimental (black) and modeled (red) normal incidence extinction (-ln(Transmission)) spectra of a gold coaxial rod-tube array surrounded by the alumina matrix. (b) and (c) longitudinal cross section of the |Ex|, component of the field along the polarization direction, for 525 and 810 nm incident wavelengths respectively. (d) and (e) charge distribution at the top surface of the CRT, at 525 and 810 nm wavelengths, respectively. Red and blue indicate opposite polarity of the charges.
(a) Optical tunability of the system was carried out by changing the diameter of the inner rod from 20 nm (black) to 25 nm (red). (b) Simulated optical response of the system when increasing nanorod diameter from 20nm (black) to 25 nm (red).
(a) Simulated refractive index sensing characteristics of the coaxial nanostructures. It is tested by varying the surrounding refractive index (n) from 1.3 (red curve) to 1.5 (dark blue curve) in steps of 0.05. (b) The bulk sensitivity of the complete coaxial structure (black line) to refractive index changes compared to only exposing the cavity (blue) and outer walls (red) for the lower energy (bounding) peak.
The geometrical tunability of the coaxial nanostructures.
Article metrics loading...