Tailored Metal‐Oxygen Bonding in Amorphous Perovskite CoSnO3 for Broadband Ultrafast Laser State Active Manipulation

Abstract Amorphous perovskite CoSnO 3 has attracted significant attention due to its unique properties and various modification methods. However, modifying metal‐oxygen bonds on the nonlinear optical (NLO) characteristics remains uncharted. In this study, a dehydration method is employed to convert the metal‐hydroxyl bonds (M─OH) of hydroxide CoSn(OH) 6 into metal‐oxygen bonds (M─O), successfully preparing amorphous CoSnO 3 with oxygen vacancies. Subsequently, effective regulation of the metal‐oxygen bonds in amorphous CoSnO 3 is achieved through an ion exchange strategy, yielding Fe‐doped CoSnO 3 (Fe‐CoSnO 3 ). Comprehensive characterization and analysis revealed that the regulation of metal‐oxygen bonds accelerated the electron transition rate, resulting in a fast recovery time of ≈245.1 fs for Fe‐CoSnO 3 , accompanied by a significant boost in broadband NLO properties. Notably, when Fe‐CoSnO 3 is utilized as a saturable absorber (SA), it exhibited superior mode‐locking characteristics compared to CoSnO 3 in the range of 1–2 µm. Specifically at the communication band of 1.5 µm, the dynamic switching between single‐wavelength and dual‐wavelength mode‐locking operations is achieved. With the ultrafast laser state manipulation, a digital encoding is also demonstrated. This work confirmed that the tailoring of metal‐oxygen bonds makes Fe‐CoSnO 3 an excellent NLO material for ultrafast optical applications, and this tailoring strategy provides new insights for designing advanced NLO materials.