Loss reduction in sharply bent optical nanofibers by coupling with Au nanoparticles.

Bending losses of sharply bent optical nanofibers or nanowires coupling with Au nanoparticles (Au NPs) are investigated using a finite-difference time-domain (FDTD) method. Relying on the ultra-tight optical confinement of the Au NPs, bending losses of the sharply bent optical nanofibers or nanowires can be effectively reduced by attaching Au NPs to the inner edge of the bent nanofibers or nanowires. At 650-nm wavelength, a bending-loss reduction of 4.7 dB/90° is obtained for a 300-nm-diameter SiO 2 nanofiber coupling with seven 140-nm-diameter Au NPs when the bending radius is 1.0 μ m. Our results suggest a potential route to realizing sharply-bent optical nanofibers or nanowires with acceptable bending losses for constructing highly compact photonic integrated circuits or devices. • Reduction of bending loss in sharply bent optical nanofiber by coupling with Au nanoparticles is proposed. • By optimizing the size, the position and the number of Au nanoparticles, the bending loss of a nanofiber can be effectively reduced. • This method is also applicable to sharply bent planar nanowaveguides. [ABSTRACT FROM AUTHOR]