  Here we show indirect precise angular control using a four-wave mixing (FWM)
process. This was performed with a superposition of light with orbital angular
momentum (OAM) in an M-Type configuration of a hot 85Rb atomic ensemble. A
gear-shaped interference pattern is observed at FWM light with a donut-shaped
input signal. The gear could be rotated and is controlled through the change of
the polarization of the pump laser. Our experimental results that are based on
nonlinear coherent interactions have applications in image processing and
precise angular control.
