Three-Photon Saturable Absorption in Atomically Thin Phlogopite

Two-dimensional (2D) materials, due to their remarkable physical and chemical properties, hold significant potential for future optical and electrical applications. In this study, the synthesis of 2D phlogopite (magnesium-rich mica) via liquid-phase exfoliation (LPE) is reported using an efficient and scalable procedure. XRD structural analysis revealed a preferential orientation along the (033) plane, whereas AFM and SEM demonstrated a nanoscale thickness and homogeneous morphology. Optical characterisation by UV-Vis and Raman spectroscopy shows tuneable band gaps up to 4.52 eV for the exfoliated 2D phlogopite and distinct vibrational modes indicative of structural evolution. At intense laser conditions, three-photon saturable absorption (3PSA) behaviour was evidenced by light-modulated electrical property studies, which emphasise the potential for optical limiting, switching, and mode-locking applications. The present investigation indicates 2D phlogopite as a versatile material for next-generation optoelectronic devices of high-intensity light modulation.