Simplified dual-comb hyperspectral digital holography system based on spatial heterodyne interferometry

Dual-comb hyperspectral digital holography (DC-HSDH) is an emerging technique employing two optical frequency combs with slightly different repetition frequencies for hyperspectral holographic imaging.Leveraging the unique capabilities of dual-comb interferometry (DCI), DC-HSDH enables the acquisition of phase maps and amplitude maps for multiple wavelengths in parallel, showcasing advantages in imaging speed and robustness.This study introduces a simplified DC-HSDH system based on spatial heterodyne DCI.It reduces the number of required optical devices in comparison to conventional DC-HSDH systems, leading to a streamlined system structure, reduced electric power consumption, and enhanced optical power efficiency.Additionally, it effectively improves the space-time bandwidth product by doubling the temporal bandwidth efficiency.Experiments were performed to validate the system.The proposed system successfully retrieved the three-dimensional profile of a stepped reflector without ambiguity, and the transmission spectrum of an absorbing gas was obtained simultaneously.