  Efficient manipulation of the emission direction of a chiral nanoscale light
source is significant for information transmission and on-chip information
processing. Here, we propose a scheme to control the directionality of
nanoscale chiral light sources based on gap plasmons. The gap plasmon mode
formed by a gold nanorod and a silver nanowire realizes the highly directional
emission of chiral light sources. Based on the optical spin-locked light
propagation, the hybrid structure enables the directional coupling of chiral
emission to achieve a contrast ratio of 99.5%. The emission direction can be
manipulated by tailoring the configuration of the structure, such as the
positions, aspect ratios, and orientation of the nanorod. Besides, a great
local field enhancement exists for highly enhanced emission rates within the
nanogap. This chiral nanoscale light source manipulation scheme provides a way
for chiral valleytronics and integrated photonics.
