Saturable absorbers are materials that exhibit nonlinear absorption properties, meaning their absorption of light changes with the intensity of the incoming beam. This property allows for dynamic control over the transmission of light, making saturable absorbers a key component in various optical devices such as mode-locked lasers, optical switches, and pulse shaping devices. Saturable absorbers work by quickly saturating at high intensities, allowing more light to pass through at lower intensities. This behavior is often exploited in ultrafast optics applications, where precise control over the timing and duration of pulses is crucial. Research in saturable absorbers focuses on developing new materials with improved nonlinear absorption characteristics, as well as exploring new applications for these materials in areas such as telecommunications, high-speed imaging, and quantum optics. Overall, saturable absorbers play a critical role in advancing the field of nonlinear optics and ultrafast photonics.