Extended Data Fig. 1: OTF comparison of 3D-SIM, four-beam SIM, and 4Pi-SIM.
From: Elucidating subcellular architecture and dynamics at isotropic 100-nm resolution with 4Pi-SIM
The first column shows the simulated OTFs for wide-field (WF) microscopy and image interference microscopy (I2M). The second column shows the illumination frequency components of 3D-SIM, four-beam SIM, and 4Pi-SIM, from top to bottom. The magenta dots indicate the additional frequency components introduced by four-beam interference, while the green dots represent frequency components further introduced by six-beam interference. The third column compares the x-z cross-sections of the illumination patterns for 3D-SIM, four-beam SIM, and 4Pi-SIM. The fourth column compares the system OTFs of 3D-SIM, four-beam SIM, and 4Pi-SIM by convolving the illumination frequency components with the detection OTFs. All the simulated OTFs are shown on a logarithmic scale for visualization purposes. The dashed line in the frequency distribution of illumination indicates the WF detection OTF. The dashed lines in the System OTF indicate WF (for 3D-SIM and four-beam SIM) and I2M (for 4Pi-SIM) detection OTF, respectively. Scale bars: 1 μm for illumination pattern in the spatial ___domain; 1/500 nm-1 for all simulated OTFs. Simulation parameters: pixel size, 30 nm; excitation NA = 1.15; emission NA = 1.27; refractive index of the immersion medium = 1.33; excitation wavelength, 488 nm; and emission wavelength, 525 nm.
