Scan-less synthetic aperture digital holography based on a dual-comb interferometer

Digital holography (DH) has become a powerful tool across various areas. However, two key performance metrics of DH systems, field-of-view (FOV) and spatial resolution (SR), are inherently constrained by the space-bandwidth product (SBP) of the system, which limits their simultaneous improvement. To overcome this limitation, conventional approaches rely on scanning devices to sequentially alter the spatial configuration of the system, thereby realizing the synthesis of different sub-apertures. However, such scanning mechanisms introduce limitations in terms of system stability, imaging speed, and overall efficiency of information acquisition. In this paper, we propose a scan-less synthetic aperture (SA) DH system based on a non-integer-ratio dual-comb interferometer. By exploiting the parallel measurement capabilities of optical frequency combs (OFCs), the data corresponding to multiple sub-apertures can be captured simultaneously. The repetition frequencies of the two OFCs were designed with a non-integer ratio to enhance the imaging speed. Experiments were performed to verify the system. The results demonstrate that 19 interferograms were recorded within 250 ms, enabling the synthesis of nine sub-apertures. The SBP was increased by approximately 7.97 times, leading to evident improvements in both FOV and SR. This scan-less SA-DH scheme offers, to our knowledge, a new methodology for high-resolution holographic imaging in the fields of life science and materials science.