  The extension of photonic technologies such as lidar and free-space optical
communications from the traditional visible and near-infrared wavelengths to
longer wavelengths can improve performance in adverse environments such as
haze, fog, smoke, or strong solar background. Non-mechanical beam steerers will
be a critical component of the low size, weight, and power modules needed for
the portable or unmanned systems deployed in these environments. In this work,
we demonstrate the first 2D optical phased array for non-mechanical beam
steering in the mid-infrared spectral region. We combine a total
internal-reflection mirror emitter with a non-redundant array of 30 elements to
carry out 2D beam steering at a single wavelength of 4.6 $\mu$m. The experiment
yielded 600 resolvable far-field points, with 2400 points over a $28^\circ
\times 28^\circ$ field of view calculated theoretically. Moreover, the device
was fabricated in a passive InGaAs/InP platform, contributing another advance
in the ongoing development of quantum cascade laser-based photonic integration.
