Individual addressing of trapped $^{171}$Yb$^+$ ion qubits using a   MEMS-based beam steering system
  The ability to individually manipulate the increasing number of qubits is one of the many challenges towards scalable quantum information processing with trapped ions. Using micro-mirrors fabricated with micro-electromechanical systems (MEMS) technology, we focus laser beams on individual ions in a linear chain and steer the focal point in two dimensions. We demonstrate sequential single qubit gates on multiple $^{171}$Yb$^+$ qubits and characterize the gate performance using quantum state tomography. Our system features negligible crosstalk to neighboring ions ($< 3\times 10^{-4}$), and switching speed comparable to typical single qubit gate times ($<$ 2 $\mu$s). 
S. Crain, E. Mount, S. Baek, and J. Kim
quant-ph physics.atom-ph