Several advantages of our mosaicing scheme should be noted. First, as a hybrid scanning approach between optical scanning and mechanical scanning, moscaicing significantly speeds up the data acquisition time of the imaging modality. With 320 kHz fiber laser, our system outperforms the G2 OR-PAM, which is introduced by Hu et al.,8 in terms of data acquisition speed. To scan a region of , 70 min is required for G2 OR-PAM, whereas, with the proposed system, only 90 s is needed for a region of . Our system is at least 20 times faster than G2 in terms of data acquisition time per unit area. Since our system has similar pixel size with G2 OR-PAM, it still surpasses G2 OR-PAM by the same factor if compared with size of dataset per unit time range. Our system is also faster than existing systems with different scanning schemes in terms of dataset size, as discussed above. This speed advantage will prove important for ease of use for end-users. Second, the mosaicing scheme significantly enlarged the FOV possible with optical-scanning OR-PAM, which is limited by the transducer focal waist. Third, since each mosaic patch is acquired in less than 0.5 s, motion artifacts per patch should be minimal and motion artifacts between different mosaic patches can be compensated for by simple image processing. This scheme may be less prone to motion artifacts over large FOVs compared to other mechanical or hybrid-scanning methods.10 Future work should validate robustness to motion in clinical scenarios. Finally, the mosaicing scheme enables multi-scale imaging with OR-PAM. As shown in Fig. 4(a) and 4(b), one can conduct a rough scan in a larger area for preliminary study and then direct the imaging system to a specific region of interest for further studies after re-adjusting the system in terms of focusing, etc. We believe the aforementioned merits will accelerate the acceptance of the imaging technique among biologists and clinicians.