Fig. 1. Three mirror model of self-mixing

Fig. 2. Imaging schematic of self-mixing interferometer

Fig. 3. Spot intensity distribution after focusing measured by knife-edge method

Fig. 4. Appropriate imaging area selected by simulation of spot size.(a) Simulation of FWHM varing with propagation distance when deviating from the focal plane (z=0); (b) image of 1-1 on resolution board by optical microscope

Fig. 5. Scanning and reconstruction results for 1-1 along x axis. (a) Amplitude under each off-focus plane; (b) reconstruction results under each off-focus plane; (c) result comparison on the focal plane; (d) result comparison on plane 2 mm away to focal plane; (e) result comparison on plane 4 mm away to focal plane

Fig. 6. Amplitude and reconstruction images of 1-1. (a)‒(c) Amplitude images on plane 0, 2, 4 mm away to focal plane; (d)‒(f) reconstruction images on plane 0, 2, 4 mm away to focal plane

Fig. 7. Variation of structural similarity of images with offset distance