Multi-scale Optics for Enhanced Light Collection from a Point Source

High efficiency collection of photons emitted by a point source over a wide field-of-view (FoV) is crucial for many applications. Multi-scale optics over improved light collection by utilizing small optical components placed close to the optical source, while maintaining a wide FoV provided by conventional imaging optics. In this work, we demonstrate collection efficiency of 26% of photons emitted by a point-like source using a micromirror fabricated in silicon with no significant decrease in collection efficiency over a 10 mm object space.Comment: 4 pages, 4 figure

Error Compensation of Single-Qubit Gates in a Surface Electrode Ion Trap Using Composite Pulses

The fidelity of laser-driven quantum logic operations on trapped ion qubits tend to be lower than microwave-driven logic operations due to the difficulty of stabilizing the driving fields at the ion location. Through stabilization of the driving optical fields and use of composite pulse sequences, we demonstrate high fidelity single-qubit gates for the hyperfine qubit of a $^{171}\text{Yb}^+$ ion trapped in a microfabricated surface electrode ion trap. Gate error is characterized using a randomized benchmarking protocol, and an average error per randomized Clifford group gate of $3.6(3)\times10^{-4}$ is measured. We also report experimental realization of palindromic pulse sequences that scale efficiently in sequence length

Efficient Collection of Single Photons Emitted from a Trapped Ion into a Single Mode Fiber for Scalable Quantum Information Processing

Interference and coincidence detection of two photons emitted by two remote ions can lead to an entangled state which is a critical resource for scalable quantum information processing. Currently, the success probabilities of experimental realizations of this protocol are mainly limited by low coupling efficiency of a photon emitted by an ion into a single mode fiber. Here, we consider two strategies to enhance the collection probability of a photon emitted from a trapped Yb ion, using analytic methods that can be easily applied to other types of ion or neutral atoms. Our analysis shows that we can achieve fiber coupling efficiency of over 30% with an optical cavity made of a flat fiber tip and a spherical mirror. We also investigate ways to increase the fiber coupling efficiency using high numerical aperture optics, and show that collection probability of over 15% is possible with proper control of aberration.Comment: 11 pages, 8 figure