  Trapped ions are a leading system for realizing quantum information
processing (QIP). Most of the technologies required for implementing
large-scale trapped-ion QIP have been demonstrated, with one key exception: a
massively parallel ion-photon interconnect. Arrays of microfabricated phase
Fresnel lenses (PFL) are a promising interconnect solution that is readily
integrated with ion trap arrays for large-scale QIP. Here we show the first
imaging of trapped ions with a microfabricated in-vacuum PFL, demonstrating
performance suitable for scalable QIP. A single ion fluorescence collection
efficiency of 4.2 +/- 1.5% was observed, in agreement with the previously
measured optical performance of the PFL. The contrast ratio between the ion
signal and the background scatter was 23 +/- 4. The depth of focus for the
imaging system was 19.4 +/- 2.4 {\mu}m and the field of view was 140 +/- 20
{\mu}m. Our approach also provides an integrated solution for high-efficiency
optical coupling in neutral atom and solid state QIP architectures.
