High-Fidelity Ion State Detection Using Trap-Integrated Avalanche Photodiodes
David Reens, Michael Collins, Joseph Ciampi, Dave Kharas, Brian F. Aull, Kevan Donlon, Colin Bruzewicz, Bradley Felton, Jules Stuart, Robert Niffenegger, P. Rich, Danielle Braje, Kevin Ryu, John Chiaverini, Robert McConnell
Abstract
Integrated technologies greatly enhance the prospects for practical quantum information processing and sensing devices based on trapped ions. High-speed and high-fidelity ion state readout is critical for any such application. Integrated detectors offer significant advantages for system portability and can also greatly facilitate parallel operations if a separate detector can be incorporated at each ion-trapping location. Here, we demonstrate ion quantum state detection at room temperature utilizing single-photon avalanche diodes (SPADs) integrated directly into the substrate of silicon ion trapping chips. We detect the state of a trapped Sr^{+} ion via fluorescence collection with the SPAD, achieving 99.92(1)% average fidelity in 450 μs, opening the door to the application of integrated state detection to quantum computing and sensing utilizing arrays of trapped ions.