Dantus' team used an approach that involves coherent
nonlinear spectroscopy.
Testing has shown how harmonic amplitudes in
nonlinear spectroscopy with the ACSTM can be interpreted in terms of molecular motions, charging and electronic structure.
Another 27 studies consider such topics as fluctuations and relaxation dynamics of liquid water revealed by linear and
nonlinear spectroscopy, charge transport at the metal-organic interface, ultrafast photochemistry in liquids, single-molecule fluorescence imaging in living cells, dynamic nuclear polarization methods in solids and solutions to explore membrane proteins and membrane systems, and molecular switches and motors on surfaces.
The combination of classical TR acoustics and
nonlinear spectroscopy brings about a significant enhancement of imaging localized areas of microdamage and is one of the only techniques known today to discriminate between a linear (void) and a nonlinear scatterer (crack).
Other topics covered include dynamics of light harvesting in photosynthesis, quantum coherent control for
nonlinear spectroscopy and microscopy, chirality in nonlinear optics, and active biological materials.
For the uninitiated, Cina explains wavepacket interferometry as "a form of
nonlinear spectroscopy using sequences of ultrashort pulses with specified optical phase relationships, to gain direct experimental information at the level of time-dependent quantum mechanical wave functions."