14 - Light Sheet Microscopy with Wavefront-Shaped Beams: Looking Deeper into Objects and Increasing Image Contrast

Summary

Light propagation through inhomogeneous, disordered materials is still an enigmatic problem with unpredictable output, since complex multi-particle light scattering results in uncountable phase delays from scattered or absorbed photons. In coherent optics, strong intensity modulations arise from the interference of ballistic and diffusive photons and thus generate deterministic chaotic intensity distributions after some dozens of microns of propagation through scattering materials such as biological tissue. This circumstance is detrimental to the quality of an image p(x,y,z) in light-sheet based microscopy (LSBM), where a thin plane within the sample is illuminated by a sheet of light. In the ideal, but unrealistic case the light-sheet consists of purely ballistic photons, which do not interact with the various scatterers inside the sample to be imaged. However, only recently it has been shown that the relative number of ballistic photons could be increased by holographically shaping the phase of the incident laser beam. This effect leads not only to enhanced penetration depths, but consequently also reduces diffusive photons or beam deflections by scattering objects.