Light-sheet fluorescence microscopy (LSFM) affords highly parallelized 3D imaging with optical sectioning capability and minimal light exposure. However, using Gaussian beams for light-sheet generation results in a trade-off between beam waist thickness and the area over which the beam can approximate a light-sheet. Novel techniques for LSFM are disclosed that uses extended focusing and/or laser line focuses to produce divergence free light-sheets with near diffraction-limited resolution and uniform intensity distribution.