Fig. 1. (a) Surface topography of three typical Bi2Te3 nanosheets. (b) Height profiles of selected nanosheets.

Fig. 2. Measured Raman spectrum of bulk Bi2Te3 and Bi2Te3 nanosheets.

Fig. 3. Nonlinear optical properties of the as-prepared Bi2Te3 SA.

Fig. 4. Optical transmission spectrum of Bi2Te3 nanosheets.

Fig. 5. Schematic setup of diode-pumped Bi2Te3Q-switched Tm:LuAG laser.

Fig. 6. Average output powers versus incident pump powers for the Bi2Te3 SA Q-switched Tm:LuAG laser (a) in CW regime and (b) Q-switching regime.

Fig. 7. Output spectra for Tm:LuAG lasers in CW regime and Q-switching regime.

Fig. 8. (a) Pulse durations, (b) repetition rates, (c) single pulse energies, and (d) peak powers as function of incident pump powers.

Fig. 9. Temporal profiles of typical pulse trains at different repetition rates and the shortest pulse shape with duration of 620 ns.

Fig. 10. M2 factors from the Bi2Te3 SA Q-switched Tm:LuAG laser at the highest output power.