TWINKLE: An open-source two-photon microscope for teaching and research
Fig 5
A) Measurement of the local magnification with a 100 μm calibration target in a thin Fluorescein film below a coverslip. Shown in green is a 700 × 700 μm2 square as reference. B) Histogram of the magnifications in A, measured across all squares. C) Two-photon intensity measurements from a uniform bath of Fluorescein. Shown are pixel values (maximum is 32768). D) Horizontal and vertical profiles through the data in C. The green box is indicated by the shaded green area. Range is ±1 standard deviation. E) Histogram of the intensities from within the green box in C. F) Volumetric measurement of a 0.2 μm bead sample in 1% Agarose. G) Average of N = 38 beads. H) Horizontal and vertical profiles through data in G and a Gaussian fit reveal a radial resolution of 760 ± 30 nm. I) Estimate of the axial resolution shows 5.4 ± 0.9 μm.