  We report numerically the efficient channeling of single photons from a
single quantum emitter into guided modes of optical nanocapillary fibers
(NCFs). The NCF is formed of a liquid core optical nanofiber with inner and
outer diameters. We optimize the inner and outer diameters of the NCF filled
with water medium by placing a single dipole source (SDS) inside. The maximum
channeling efficiency of 52% is found when the radially polarized SDS is placed
at the center of the NCF filled with the water medium. The optimum inner and
outer diameters of the NCF are 100 nm and 360 nm for the emission wavelength of
620 nm, respectively. Additionally, we investigate the SDS position dependence
inside the NCF considering experimental ambiguity in placing a single quantum
emitter inside the NCF. We found that the channeling efficiency remains almost
constant for the water medium at the optimum condition. The present platform
may open a novel route for generating single photons in quantum technologies
and detecting single cells in bio-sensing.
