a, Reduction of side-lobes in 3D-iLLS imaging using deconvolution. Top: raw z profiles of two individual mRNA molecules, from the data in Fig. 2a. Bottom: z profiles of the same mRNAs, after 10 iterations of the Richardson-Lucy deconvolution algorithm with an experimental PSF. b-i, Optimized 3D-iLLS PSF based on a fundamental rectangular 2D bound lattice. b, SLM pattern and c, corresponding intensity at rear pupil. d Annular mask. e, Intensity at rear pupil after annular mask. f, Resulting 2D bound lattice in real space and g, corresponding dithered lattice excitation pattern. h, Axial profile of conventional LLS PSFs. i, Axial profile of 3D-iLLS PSFs. Cyan: excitation; yellow: detection; gray: overall.