Microscopy with non-diffracting beams

The quality of a three dimensional image of a structure is mainly determined by spatial resolution and contrast. Tremendous progress has been achieved for thin specimen in terms of optical resolution during the last years. However, in thick specimen, such as in cell clusters or even whole organisms, light scattering and absorption still reduce image contrast and resolution. Motivated by the concept of self-reconstructing beams, we present a microscope where a phase modulated beam propagates through a specimen in a direction perpendicular to the detection optical axis. The fluorescent excitation beam is modulated in phase by a spatial light modulator (SLM) such that the beam’s angular spectrum obtains a typically delta-like shape, as e.g. with Bessel beams. In this way, momentum transfer and coherent scattering are reduced inside the object to be imaged. In the talk we present both the setup and the functionality of this new type of microscope and discuss the ability of such beam modes to self-reconstruct even in strongly scattering media. Results including 3D images of bead clusters and cells are presented and discussed.