Individual atoms can act as stationary qubits and thus serve as nodes in quantum computing networks or as memories for quantum repeaters. However, to successfully use qubits based on single atoms suspended in free space, photons emitted by a single atom need to be efficiently collected. Conventionally, this can be done with high numerical aperture lenses, which can collect light from a large solid angle. Alternatively, placing the atom into a high-finesse cavity or within a sub-wavelength distance from the surface of a nano-photonic structure can affect the spatial pattern in which the atom emits photons and make the photon collection more efficient. However, these approaches remain experimentally challenging and can limit the potential for realistic scalability.
This project aims to achieve a distinctly novel way to control the emission pattern of a single atom by placing the atom at a distance of a few wavelengths from a chiral metasurface — a phased two-dimensional array of nano-scale metallic antennas or dielectric scatterers. We design and fabricate bi- and multi-layer structures with properly tuned interference between the radiation patterns of the layers. In the vicinity of such structures, the atom will emit light into a single, well defined direction without the need to place the atom at a sub-wavelength distance from a metallic or dielectric surface. The unidirectionally emitted photons can be efficiently coupled into optical fibers. Relative to current state-of-the-art, this platform simplifies and enables speed-up for certain quantum information processing tasks, such as remote entanglement between two distant atoms.
Simultaneously we will explore – through design and fabrication – the use of chiral metasurfaces for photon extraction from solid-state quantum emitters, such as colour centers in diamond. Here we hope to achieve increased photon collection efficiency from materials with high refractive index, which holds promise for improving the performance (speed and sensitivity) of electric and magnetic field sensors.
Silicon Platform for Electron Spin Qubits
Summary Scaling solid-state quantum processors to a useful threshold while maintaining the requisite precision in quantum control remains a challenge. We propose a quantum metal-oxide-semiconductor (QMOS) architecture operating at cryogenic temperatures that is based on a network/node approach as a means to scalability. By working with QMOS, we benefit from the deep investments and […]
December 7, 2018
Engineering and Characterizing Programmable Interaction Graphs in a Trapped Ion Quantum Simulator
Summary Quantum simulators have the potential to bring unprecedented capabilities in areas such as the discovery of new materials and drugs. Engineering precise and programmable interaction graphs between qubits or spins forms the backbone of simulator applications. The trapped ion system is unique in that the interaction graph between qubits can be programmed, in […]
July 24, 2018
Implementing High-fidelity Quantum Gates in Multi-level Trapped Ions
Summary The scalability of quantum processors is limited by current error rates for single-qubit gates. By encoding more than a single bit of information within a single ion, multi-level “qudits” offer a promising method of increasing the information density within a quantum processor, and therefore minimizing the number of gates and associated error rates. […]
July 30, 2018
Tuning Spin-Exchange Interactions in Low-Dimensional Metal Halide Perovskites: A New Class of Semiconductor Quantum Materials
Summary Leakage current in electronic components is one of the limiting factors for the performance of conventional computers which use charges and currents as physical information carriers. Spintronics offers an alternative by using electron spin for information transfer, processing and storage, enabling the design of non-volatile computer memory and more energy-efficient electronic devices. In this […]
October 1, 2019