ABSTRACT
The problem of exciting a nanosphere by an external light has been extensively studied in the literature. In this paper, a far-field simulation and analysis is provided for the problem of a nano/micro-sphere excited by a subwavelength laser (800 nm wavelength) as a part of a wireless communication system. The simulation is done using a full-wave finite-element method based multiphysics solver. Nonparaxial Gaussian beam formulation, which is based on plane wave expansion, is utilized to simulate an accurate subwavelength laser. Evanescent fields are included in the expansion which help in simulating the tightly focused Gaussian beam. The subwavelength laser beam is accurate as it drops to exactly 1/e of its peak at the spot radius distance. The studied sphere is swept from 100 nm to 1000 nm while the subwavelength laser spot radius is swept from 600 nm to 800 nm. The relationship between ratio of scattered power to absorbed power and ratio of subwavelength laser spot radius to sphere radius is discussed in this work. Far-field antenna quantities are calculated and a nano/micro-scale spherical antenna is optimized for optimum sphere radius and subwavelength laser spot radius.
