Smith runs Melbourne's time-resolved fluorescence facility and specialises in the information channels most people throw away: fluorescence lifetime, anisotropy decay and its orientational content, and single-molecule photophysics, applied to organic semiconductors, energy-transfer systems and biological samples. The group builds its own confocal microspectroscopy instrumentation for time-resolved anisotropy imaging and single-molecule detection. 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 — lifetime- and orientation-resolved fluorescence is the principal orthogonal contrast mechanism to spin-based sensing, and his instrumentation is the natural correlative partner for NV-ensemble DEER/relaxometry experiments at pT/sqrt(Hz) that need an independent optical readout of the same specimen. Preferred attribute present: orientation- and lifetime-resolved methods.

The Stern Group explores fundamental quantum interactions of photons with 2D materials, nano-scale structures, and atoms. Key thrusts: (1) Valley-selective exciton-polaritons in monolayer transition-metal dichalcogenides (MoS₂, MoSe₂, WSe₂) embedded in optical microcavities — hybrid light-matter quasiparticles with valley-selective polarization and cavity-modified dynamics; (2) 2D semiconductor quantum emitters — quantum-dot-like single-photon emitters formed by confinement in TMD nanoribbons and by chemical functionalization/strain engineering of defects; (3) Astrophotonics: collaboration with Argonne National Laboratory and the Australian Astronomical Observatory to design and fabricate silicon ring-resonator photonic circuits for OH sky-background suppression in near-IR astronomical spectrographs; (4) Quantum non-reciprocal photonics in axisymmetric microresonators. Experimental tools: time-resolved spectroscopy, single-photon counting, nanofabrication. DOE Early Career Award; ONR Young Investigator Award; Sloan Research Fellow 2013. Affiliated with Fermilab-Northwestern CAPST.

Uses ultrafast multidimensional spectroscopy to study structural dynamics of biomolecules. Directions: (1) 2D IR spectroscopy of protein folding, water dynamics, and membrane systems with sub-100-fs time resolution; (2) single-molecule FRET for resolving conformational heterogeneity in proteins and nucleic acids; (3) development of ultrafast mid-IR laser sources and pulse shaping for 2D spectroscopy. Resolves dynamics inaccessible to other methods.

Develops multidimensional coherent spectroscopy methods, including label-free multidimensional optical imaging/contrast techniques applied to cancerous tissue and nanoscale heterostructures.

Develops multidimensional (2D IR/visible) ultrafast spectroscopy and new ultrafast optical microscopies, applying temporally- and spatially-resolved coherent spectroscopy to protein structure/dynamics and label-free tissue imaging.