  We control the relative coupling strength of carrier and first order motional
sideband interactions of a trapped ion by placing it in a resonant optical
standing wave. Our configuration uses the surface of a microfabricated chip
trap as a mirror, avoiding technical challenges of in-vacuum optical cavities.
Displacing the ion along the standing wave, we show a periodic suppression of
the carrier and sideband transitions with the cycles for the two cases
$180^\circ$ out of phase with each other. This technique allows for suppression
of off-resonant carrier excitations when addressing the motional sidebands,
with applications in quantum simulation and quantum control. Using the standing
wave fringes, we measure the relative ion height as a function of applied
electric field, allowing for a precise measurement of ion displacement and,
combined with measured micromotion amplitudes, a validation of trap numerical
models.
