This paper describes a synthetic aperture common-path digital holographic microscopy through phase-shifting in a rotating spiral phase filter (SPF) to strengthen axial phase accuracy and fully utilize frequency coverage to improve of the spatial resolution. A phase-type liquid crystal on a silicon spatial light modulator was employed to generate an SPF on the Fourier plane of the digital holographic microscopy system. Subsequently, the scattering wave passing through the spiral phase plate and the reference wave generated through the center of phase plate as a spatial filter were used for the interference process, thereby completing the recording of the on-axis digital hologram. The common-path digital holographic microscopy system integrated with synthetic aperture imaging can be applied for Fresnel hologram recording and numerical focusing on objects without being affected by environmental vibration and coherence, thereby improving the spatial resolution and axial phase accuracy.
