Squeezing light into subwavelength metallic tapers: single mode matching method

Abstract

Abstract.A simple single mode matching (SMM) method is proposed to analyze the optical throughput for subwavelength metal tapers. Both a 2D gold-clad taper gap and a 3D gold taper rod are analyzed with the SMM method. Including metal losses, these structures are calculated to have optimal squeezing taper angles of 14° with 71% efficiency and 32° with 44% efficiency, which is in good quantitative agreement with previous finite-difference timedomain simulations. The SMM method uses only analytic calculations and 2-by-2 matrix multiplication. Therefore, compared to past approaches, the SMM method is an efficient method to optimize the subwavelength metallic taper structures, while including losses, and it can be extended to more complex tapers and gratings in an obvious way. It also has the potential for fully analytic calculations.