(a) Scheme of the reflected light-sheet principle developed by Gebhardt et al. in 2013.26 A laser beam is focused by an objective to form a vertical light sheet that is reflected by a 45° atomic force microscopy cantilever next to a cell in a Petri dish. Fluorescence is detected by a second high-NA objective. (b) Schematic representation of the single-objective light sheet-microscope developed by Galland et al. in 2015.27 A light sheet is created by reflection from a 45° micromirror. The light sheet is projected from the detection objective. (c) Comparison of methods in LSFM. (A) Traditional Gaussian beam LSFM. (B) Bessel beam LSFM has a much narrower core. However, Bessel beams exhibit concentric side lobes that tend to degrade the axial resolution. (C and D) Bound optical lattices create periodic patterns of high modulation depth across the plane, greatly reducing the peak intensity and the phototoxicity in live-cell imaging. The square lattice in (C) optimizes the confinement of the excitation to the central plane, and the hexagonal lattice in (D) optimizes the axial resolution. Scale bars are 1.0 mm except for the xz cross-section of the overall PSF of the microscope (scale bar, 200 nm). Part (c) reprinted by permission from AAAS: B. C. Chen, W. R. Legant, K. Wang, L. Shao, D. E. Milkie, M. W. Davidson and E. Betzig. Lattice light-sheet microscopy: imaging molecules to embryos at high spatiotemporal resolution. Science, 2014, 346, 1257998. Copyright © 2014, Science.