  It has recently been shown that optical reflection gratings fabricated
directly into an atom chip provide a simple and effective way to trap and cool
substantial clouds of atoms [1,2]. In this article we describe how the gratings
are designed and micro-fabricated and we characterise their optical properties,
which determine their effectiveness as a cold atom source. We use simple scalar
diffraction theory to understand how the morphology of the gratings determines
the power in the diffracted beams.
