Abstract

We propose a scheme in which the position of an atom passing through a standing wave light field may be localised to much less than the wavelength of the light. We contrast this with the resolving power of a Heisenberg microscope which can be no better than the wavelength of the scattered light it detects. The essence of our proposal is as follows. When a two level atom is passed through a standing wave mode in an optical cavity the atom inflicts a phase shift on the field which is position dependent. By making a quadrature phase measurement on the field it is possible to localise the position of the atom very precisely within a wavelength of the light in the cavity. The use of a similar arrangement has been proposed to measure the photon number of the field, either by measuring the atomic phase^[1] or by measuring the atomic deflection^[2].

© 1992 IQEC