Mxene Ti₃C₂Tx Langmuir–Blodgett films as saturable absorber for near-infrared Q-switched laser

MXene is a fast-growing family of 2D materials with unique light–matter interactions. Ti₃C₂Tx belongs to the family of MXene that show nonlinear saturable absorption characteristics and has been studied widely. However, translating the excellent performance of MXene flakes into stable thin film saturable absorbers (SA) devices has been a challenging task. Herein, we report the fabrication of a long term stable MXene Ti₃C₂Tx film SA deposited on a quartz plate by the Langmuir–Blodgett (LB) method for the first time, and it was used in passive Q-switched solid-state pulsed laser generation at the central wavelengths of 1.06 and 1.34 μm, respectively. LB Ti₃C₂Tx SAs exhibits excellent optical properties such as high modulation depth, low loss, and high linear transmittance at mid-infrared wavelengths. By inserting the LB Ti₃C₂Tx SAs into two Nd-doped solid-state lasers, short pulses were generated with the pulse duration of 244 ns and 311 ns in the 1.06 and 1.34 μm regimes, respectively. In addition, long-term stability was maintained in constant temperature drying. The results illustrate the potential of the MXene LB Ti₃C₂Tx SA films for laser applications, paving new ways for producing large-area, ultra-uniform, low-loss and stable MXene SA by the LB method.