Robust and efficient optical limiters based on molybdenum disulfide nanosheets embedded in solid-state heavy-metal oxide glasses

Abstract

Simple and effective methods are needed to incorporate two-dimensional functional materials with distinctive nonlinear optical (NLO) response into appropriate solid-state matrices while maintaining inherent functionalities for practical applications in optoelectronic fields. Here, ultrathin molybdenum disulfide (MoS2) nanosheets and lead silicate (PbO-SiO2) gel glasses were chosen as a representative guest dopant and mother matrix, respectively. The MoS2 was introduced into the PbO-SiO2 binary gel glasses by a simple sol-gel wet chemical technique to obtain transparent and s three-dimensional monolithic bulk materials. The presence of MoS2 in the gel glasses and the formation of binary gel glasses were confirmed by various techniques. The NLO and optical limiting (OL) performances were investigated by both open-aperture (OA) and closed-aperture (CA) Z-scan techniques on nano- and picosecond timescales with the use of a laser operating at 532 nm. Our results demonstrate that the NLO effect of MoS2/PbO-SiO2 binary gel glasses was greater than that observed for MoS2/SiO2 unary gel glasses because of enhanced third order nonlinear susceptibility effects induced by the heavy metal. The OA and CA Z-scan patterns suggested that the NLO response of the MoS2/PbO-SiO2 gel glasses is mainly attributed to their nonlinear absorption and nonlinear refraction. Remarkably, the extracted OL thresholds of the MoS2/PbO-SiO2 gel glasses were 12.4 and 7.8 times as great as those recently reported in a MoS2 suspension at nanosecond timescale and MoS2/PMMA organic glass at the picosecond timescale, respectively. The present results demonstrate the feasibility and versatility of MoS2/PbO-SiO2 silica gel glasses, as a new class of highly efficient NLO and OL materials that can be applied in the field of nonlinear optics.