Fig. 1. Three primary fluorescence polarization techniques. (a) Schematic diagram of single molecule and wide-field imaging^[22]; typical setup of (b) fluorescence anisotropy, (c) linear dichroism, and (d) defocused imaging^[24]; (e) result of fluorescence anisotropy imaging; (f) linear dichroism imaging result; (g) defocused imaging result

Fig. 2. Researches on motor proteins using fluorescence polarization. (a) Schematic diagram of kinesin (left), dynein (right), and myosin ^[35-36]; (b) results of research on dynein^[10]; (c) walk pattern of motor proteins ^{[10, 30, 35]}; (d) relationship between angle changes and time in defocused imaging of myosin ^[34]

Fig. 3. Image of membrane structure using fluorescence polarization. (a) Orientation and wobbling angles of membrane probes analyzed by polarization parameters combined with Fourier series analysis (scale bar:10 μm) ^[26]; (b) imaging analysis of DPPC with 40% cholesterol (scale bar:2 μm) ^[39]; (c) imaging of calcium sensor labelled by cpVenus, using two-photon microscopy (scale bar: 5 μm)^[19]; (d) image of membrane using two-photon microscopy based on tunable linear dichroism^[18]; (e) defocused image of lipid membranes^[40]

Fig. 4. Research results on membrane phases using fluorescence polarization. (a) Imaging results using combined polarized AFM/TIRF (scale bar:5 μm) ^[11]; (b) imaging results using combined SMLM/SMOLM ^[44]

Fig. 5. Researches on DNA. (a) Imaging of λ-DNA^[47]; (b) research on the stretching properties of DNA^[48-49]

Fig. 6. Researches on cytoskeleton. (a) Model diagram of actin and microtubules^[55]; (b) schematic diagram of septin arrangement during yeast budding^[56] and septin-GFP fluorescence polarization imaging (the short purple line indicates the polarization direction)^[51]; (c) GS-SDOM of Alexa Fluor 568 phalloidin-labeled actin fluorescence intensity imaging (scale bar: 1 μm)^[54]; (d) selecting three structural magnifications of Fig. (c) (scale bar: 200 nm)^[54]; (e) imaging of microtubule structures in live U2OS cells using pSIM and fluorescence microscopy with PM ^[14]

Fig. 7. Researches of Nuclear pore complexes and hippocampal neurons. (a) Human nuclear pore complex model diagram and anisotropic imaging diagram of yeast Nic96-GFP^[58]; (b) traditional widefield and SPoD images of hippocampal neurons, the latter allows to see more details^[21]; (c) OLID-SDOM imaging of dendritic spines stained by lipophilic tracer Dil in living hippocampal neurons in vivo^[23]

Fig. 8. Polarization information obtained through defocus imaging. (a) Observe the movement trajectory of macrophages using SERS nanorod labeling ^[60]; (b) MFM image of a platelet aggregate composed of five cells^[61]; (c) defocused images of rotational diffusion in PMA thin films over time ^{[63, 65]}; (d)research on the binding mechanism driven by surface chemistry and structural recognition of cellulose^[64]