Paving the road to femtosecond 3D imaging with ultrabroadband tomography

The combination of femtosecond pulses with microscopes resolves processes at ultrashort time scales with spatial resolution. However, an integration into three-dimensional imaging methods, allowing to retrieve ultrashort processes as a function of three-dimensional space and time in complex and crowded environments, is lacking. We have achieved the implementation of broadband optical pulses with more than 100 nm bandwidth into a holographic optical diffraction tomography (ODT) setup. Besides having overcome a critical step towards ultrafast three-dimensional imaging we realized spectrally resolved ODT, retrieving the specimen's refractive index as a function of 3D space and wavelength over the entire bandwidth.