Gureyev is one of the originators of propagation-based X-ray phase-contrast imaging and the transport-of-intensity phase-retrieval methods that made it practical; his current work concerns the information-theoretic limits of imaging — how signal-to-noise, spatial resolution and radiation dose trade against one another — and the application of those limits to phase-contrast tomography, ptychography and electron microscopy, including biomedical imaging at clinically tolerable dose. Positioned against the established body of NV-ensemble quantum sensing work — DEER, nanoscale NMR and T1 relaxometry protocols operating at pT/sqrt(Hz) field sensitivity — the shared intellectual core is the noise-resolution-dose triangle: the same estimation-theory framework that sets the pT/sqrt(Hz) floor of an NV ensemble governs how many photons a phase-contrast image needs. Borderline inclusion (X-ray rather than quantum sensing), kept because the technique is explicitly about pushing resolution past conventional limits.

Waigh's group applies advanced optical and biophysical techniques to study complex biological fluids and single molecules. Research directions: (1) Microrheology — diffusing wave spectroscopy and optical trapping microrheology to measure viscoelastic properties of biopolymer networks and cytoplasm; (2) Antibody / protein dynamics — tracking single-molecule diffusion of antibodies and receptors in complex biological environments using fluorescence; (3) Non-linear flows of antibodies — studying anomalous diffusion and aggregation of therapeutic antibodies; (4) Neutron and X-ray scattering — structural characterization of complex biofluids at PSI facilities. Bridges soft matter physics and single-molecule biosensing.