  We describe a dynamic magneto-optical trap (MOT) suitable for the use with
vacuum systems in which optical access is limited to a single window. This
technique facilitates the long-standing desire of producing integrated atom
chips, many of which are likely to have severely restricted optical access
compared with conventional vacuum chambers. This "switching-MOT" relies on the
synchronized pulsing of optical and magnetic fields at audio frequencies. The
trap's beam geometry is obtained using a planar mirror surface, and does not
require a patterned substrate or bulky optics inside the vacuum chamber.
Central to the design is a novel magnetic field geometry that requires no
external quadrupole or bias coils which leads toward a very compact system. We
have implemented the trap for $^{85}$Rb and shown that it is capable of
capturing 2 million atoms and directly cooling below the Doppler temperature.
