Orientation paper selected for spotlight on optics

Our paper on the Single Molecule Orientation Ambiguity has been selected for a Spotlight on Optics by the Optical Society of America.

Spotlight Summary

Read the original paper here.

Spotlight Summary by Matthew D. Lew

Surface orientation ambiguity for single molecules at dielectric interfaces

A longstanding but largely unnoticed modeling gap has been skewing how researchers interpret the behavior of single molecules at interfaces—this work finally resolves it. Defocused fluorescence microscopy is widely used to infer molecular orientation, yet conventional models of dipole emission near refractive‑index boundaries diverge from one another depending on which side of the interface the molecule approaches. The result has been hidden, systematic biases in measured orientations. By treating emitters as finite-sized surface currents in contact with both media within finite-element simulations, this study provides the first physically self‑consistent framework for describing dipoles at arbitrary dielectric interfaces. Notably, the predicted radiation pattern changes dramatically as a molecule moves near the interface, necessitating care in modeling other factors like surface roughness. The implications extend well beyond microscopy: correcting these biases will sharpen measurements across biophysics, nanophotonics, organic electronics, and the engineering of optoelectronic and quantum-emitting materials where orientation dictates performance. By establishing a unified standard for modeling interfacial dipoles, this work sets the stage for new experimental tests and more reliable insights into molecular behavior at surfaces.