Abstract
Atom location, atom dipole polarisation and the order of excited mode are the principal factors governing the structure influences in a hollow optical fiber such as, enhancement or complete suppression of dipole emission rate in presence of the structure mode. In a hole diameter of the optical fiber of the order of 2-10 mu m, only the fundamental mode with cut-off frequency 0.3 PHz can exist. This means that the system operates as an exact mono-mode optical fiber and the atom propagation maintains coherence. In the slow atom approach, the electric dipole moment vector is strained by the structure mode to ensure the electric field vector at the instantaneous position of the dipole. Therefore, the polarisation gradient of slow atom controls every effect emerging in the presence or absence of the structure mode. The influence of the slow atom approach is examined with reference to certain cases, involving sodium atoms in hollow mono-mode optical fiber. The role of the fundamental mode in the atomic motions is considered.