Fig. 3.

Comparing illumination patterns: a: Fluorescence image of a Gaussian beam focussed into a cuvette containing the fluorophore Rhod-6G. Z-axis profiles at different locations along the beam (indicated by colored dotted lines on the left) are shown on the right. b: Illumination patterns obtained by frequency-swept standing wave illumination shown for 4 example spatial frequencies (stacked images). c: Fourier-transform (along the spatial frequency dimension) of the data set represented in b and profiles at different x-positions (right) traces are offset for clarity.