Abstract: A plasmonic beam splitter based on metal nanowire structure is proposed. The beam splitter consists of three straight nanowires and one annular nanowire, and has one input port and two output ports. By injecting circular polarized light at the input port, the excited surface plasmon polaritons (SPP) propagate forward along the nanowire. The radiance ratio of the light intensity at both ports of the beam splitter is analyzed by using the finite difference time domain method. The results show that the ratio of the light intensity of the two output ports is susceptible to the angle between the input and the output ports and between the two output ports. The light intensity ratio of two output ports can be adjusted by adjusting the angle between the output and the input port or the angle between the two output ports. By optimizing the structural parameters, a plasmon beam splitter that can adjust beam splitting ratio in a wide range is realized for the communication wavelengths of 1310nm and 1550nm. These properties show the potential of SPP beam splitter in photonic device integration and sensing equipment in future.

Key words: surface plasmon polaritons, beam splitter, finite-difference time-domain, nanowires