Direct wavefunction measurement

Accurately determining the state of a quantum system in a fast, efficient and accurate fashion is one of the challenges faced by experimentalists. We are currently devoloping new ways to directly measure a quantum wavefunction through the process of weak measurement.

See here for relevant work:

Full characterization of polarization states of light via direct measurement, JZ Salvail, M Agnew, AS Johnson, E Bolduc, J Leach and RW Boyd, accepted for Nature Photonics

Tomography of the quantum state of photons entangled in high dimensions Megan Agnew, Jonathan Leach, Melanie McLaren, F. Stef Roux, and Robert W. Boyd Phys. Rev. A 84, 062101

Entangled photonic
systems

One of the group's interests is the generation and detection of high-dimensional Bell states and their application to secure communication protocols, such as quantum key distribution and superdense coding.

See here for relevant work:

Secure information capacity of photons entangled in many dimensions, J Leach, E Bolduc, D J Gauthier, and RW Boyd Phys. Rev. A 85, 060304

Quantum correlations in optical angle and orbital angular momentum variables J Leach, B Jack, J Romero, AK Jha, AM Yao, S Franke-Arnold, DG Ireland, RW Boyd, MJ Padgett, Science 329 (5992), 662-665

Experimental high-dimensional two-photon entanglement and violations of generalized Bell inequalities AC Dada, J Leach, GS Buller, MJ Padgett, E Andersson Nature Physics 7 (9), 677-680

Super-resolution imaging

Our ability to resolve details in images is limited by the wavelength of the light we can detect. We are looking at using quantum states of light and novel detection schemes to increase the resolving power of imaging systems.

See here for relevant work:

Experimental realization of optical eigenmode super-resolution, K Piche, J Leach, AS Johnson, JZ Salvail, MI Kolobov, RW Boyd Optics Express 20 (24), 26424-26433