Abstract
We have shown how to evaluate the force created by a monochromatic light beam when this beam presents an intensity gradient. We have calculated this dipole force first for a simple "two-level atom" model, then for a more realistic atomic transition model. We have shown that this force derives from a potential, called the dipole potential, which is proportional to light intensity in the low-flux limit. We have also evaluated the role of spontaneous emission processes, which can create undesirable heating of trapped atoms.
