Optical beam steering is key for optical communications, laser mapping
(LIDAR), and medical imaging. For these applications, integrated photonics is
an enabling technology that can provide miniaturized, lighter, lower cost, and
more power efficient systems. However, common integrated photonic devices are
too power demanding. Here, we experimentally demonstrate, for the first time,
beam steering by microelectromechanical (MEMS) actuation of a suspended silicon
photonic waveguide grating. Our device shows up to 5.6{\deg} beam steering with
20 V actuation and a power consumption below the μW level, i.e. more than 5
orders of magnitude lower power consumption than previous thermo-optic tuning
methods. The novel combination of MEMS with integrated photonics presented in
this work lays ground for the next generation of power-efficient optical beam
steering systems