Fig. 2.

Cylindrical zoom beam expander. The configurations for a large zoom (a) and a small zoom (b) are shown. For a large zoom the beam diameter incident at the illumination objective is large in z-direction and hence the optical sectioning thickness is decreased compared to a small zoom. Lenses C2 and C4 are coupled and mounted together on a micrometer stage (not shown), so that a single motion readjusts the zoom factor. (c, top view) The incident beam diameter along y-direction is limited by a vertical slit aperture (VS), which defines the lateral width of the light sheet. The beam is focused into the back-focal-plane (BF) of the illumination objective by cylindrical lens C6. Exemplary images of the produced light sheets were shown on the right hand side (see section 2.3).