20-GHz Structured Optical Frequency Combs via Temporal and Spatial Modulation

Optical frequency combs (OFC) are widely recognized as an important light source with significant applications [1]. Customizable transverse mode structure and electro-optic frequency combs' high-repetition-rate and strong tunability are highly desirable in fields such as optical trapping and imaging [2], [3]. Modulating OFC in free space, a structured OFC can be generated, enabling the advantages of OFC while incorporating features unique to structured light, such as diffraction-free, self-healing, and carrying orbital angular momentum (OAM). In this work, we demonstrate a source capable of generating a high-repetition-rate structured OFC, with customizable transverse mode structures and tunable repetition rates, whose output power reaching several hundreds of mW.