A monolithic array of three-dimensional ion traps fabricated with conventional semiconductor technology

The coherent control of quantum-entangled states of trapped ions 1 has led to significant advances in quantum information 2 , quantum simulation 3 , quantum metrology 4 , 5 and laboratory tests of quantum mechanics 6 and relativity 7 . All of the basic requirements for processing quantum information with arrays of ion-based quantum bits (qubits) have been proven in principle 8 . However, so far, no more than 14 ion-based qubits have been entangled with the ion-trap approach 9 , so there is a clear need for arrays of ion traps that can handle a much larger number of qubits 10 . Traps consisting of a two-dimensional electrode array 11 have undergone significant development, but three-dimensional trap geometries can create a superior confining potential. However, existing three-dimensional approaches, as used in the most advanced experiments with trap arrays 8 , 12 , cannot be scaled up to handle greatly increased numbers of ions. Here, we report a monolithic three-dimensional ion microtrap array etched from a silica-on-silicon wafer using conventional semiconductor fabrication technology. We have confined individual 88 Sr + ions and strings of up to 14 ions in a single segment of the array. We have measured motional frequencies, ion heating rates and storage times. Our results demonstrate that it should be possible to handle several tens of ion-based qubits with this approach. A monolithic array of three-dimensional microtraps is etched from a silica-on-silicon wafer and is characterized by confining and probing individual ions and strings of ions.