Hyperspectral digital holography realized by using an electro-optical frequency comb via injection locking

Abstract

Hyperspectral digital holography (HSDH) is a versatile holographic imaging technique that offers large unambiguous depth range and spectroscopic information. In this Letter, we propose a novel, to the best of our knowledge, HSDH system that is realized by using an electro-optical frequency comb (EOFC) via injection locking. In comparison with conventional dual-comb HSDH, the proposed system only requires one EOFC and few other devices, which not only simplifies the system structure and reduces the cost but also improves the imaging speed. We validated the system using an EOFC with 20 optical frequencies spaced at 18 GHz intervals. In a total measurement time of 0.5 s, we successfully captured images of two targets that were 0.74 mm apart without phase ambiguity and obtained the transmission spectrum of an absorbing gas simultaneously. This work provides valuable insights for HSDH systems relying on an optical frequency comb.