  This paper presents a coherent linking approach between confocal amplitude
and confocal phase images acquired using dual-comb microscopy (DCM). DCM
combines the advantages of confocal laser microscopy and quantitative phase
microscopy, offering high axial resolution and scan-less imaging capability. By
exploiting the coherence between confocal amplitude and phase images within the
same DCM system, we accurately determine the number of phase unwrapping
iterations, eliminating phase wrapping ambiguity. The method is demonstrated
with samples having micrometer-range optical thickness and nanometer-scale
surface roughness. The results showcase an expanded axial dynamic range,
ranging from micrometers to millimeters, while maintaining nanometer-level
axial resolution. This coherently linked DCM imaging technique enables the
simultaneous acquisition of absolute phase information, enhancing its potential
for high-axial-resolution imaging in a wide range of applications.
