Enhanced Saturable Absorption in Nanowires via Wide Bandgap

Nanowires exhibit exceptional saturable absorption capabilities in the ultraviolet and visible light spectrum due to their wide bandgap. This unique characteristic allows for easy excitation of single-photon absorption at 355 nm and excited-state absorption at 532 nm. The wide bandgap energy difference between the valence and conduction bands enables efficient absorption of photons with energies matching the bandgap, resulting in strong single-photon absorption at 355 nm. Additionally, the wide bandgap facilitates efficient excited-state absorption at 532 nm by providing a large energy separation for excited electrons to transition to higher energy levels. These remarkable properties make nanowires highly promising materials for diverse optical applications, including optical switching, mode-locking, and optical limiting.