1：Experimental Design and Method Selection:

The study utilized PbS nanoparticles as a saturable absorber in a Dy3+-doped ZBLAN fiber laser setup to achieve tunable passively Q-switched operation around 3 μm.

2：Sample Selection and Data Sources:

PbS nanoparticle dispersion was synthesized using the sol-gel method. The laser setup included a homemade Yb3+-doped fiber laser as the pump source and a Dy3+-doped ZBLAN fiber as the gain medium.

3：List of Experimental Equipment and Materials:

Equipment included a homemade Yb3+-doped fiber laser, Dy3+-doped ZBLAN fiber, PbS nanoparticle dispersion, and various optical components like dichroic mirrors and off-axis parabolic reflectors.

4：Experimental Procedures and Operational Workflow:

The laser's wavelength was tuned using a plane ruled grating in a Littman configuration. The output power, temporal behavior, and optical spectrum were monitored.

5：Data Analysis Methods:

The nonlinear absorption of PbS NPs was characterized using a power-dependent measurement setup, and the laser's performance was analyzed based on output power, pulse width, and repetition rate.