Contrast optimization of two-photon processes after a microstructured hollow-core fiber demonstrated for dye molecules

We demonstrate selective excitation of dyes with overlapping absorption spectra in solution with pulses transmitted through a hollow-core fiber. Thereto we show how dispersive effects occurring in the fiber can be compensated and what the limiting pulse energies are. Furthermore, an overview over various phase parameterizations is given and we examine which are best used when optimizing a two-photon fluorescence contrast of two dyes in a sample. This could be relevant for future endoscopic applications as well as state of the art two-photon microscopy.