Nanocrescent antenna as a transceiver for optical communication systems

A novel Metal Dielectric Metal (MDM) nanocrescent antenna is presented in this paper. It is formed by locating a gold circular patch, on the top of a circular aperture etched within a 30 nm gold plate. The vertical spacing between the two gold layers is filled with Al₂O₃. The centers of both aperture and patch are not on top of each other, resulting in a crescent-shaped nantenna. This nantenna can be fed by a nanostrip line connected to the patch. The proposed nantenna can be tuned to operate at any wavelength of interest by optimizing its geometrical parameters. It offers a relative electric field intensity enhancement of 780 with a FWHM of 960 nm centered around 1550 nm, which is equivalent to more than 61% fractional bandwidth compared to 35% of the conventional dipoles and bowties. Analysis of the proposed nanoantenna is performed using two well-known full-wave electromagnetic solvers. Very good agreement between the two solvers is achieved. A geometrical parametric study is presented, which illustrates the impact of varying different nantenna dimensions on its spectral response. The sensitivity of the response to the used metal type is investigated. The radiation properties of the proposed antenna as a transmitter has been also studied.