A micron-scale laser-wire system was constructed and tested at the Accelerator Test Facility (ATF) extraction line at the High Energy Accelerator Research Organisation (KEK) in Japan. The system was evaluated through collision tests, electron beam tests, laser beam measurements and simulations. Beam halo measurements were carried out in order to compare the beam halo to a theory of its production through gas scattering and towards evaluating it as a source of background for diagnostic instruments at ATF2 and the International Linear Collider (ILC). Simulations were carried out to test the signal extraction of the system at the future ATF2 and of a similar system in the proposed ILC beam delivery system, with implications for sharing the signal extraction region with the polarimeter.