1：Experimental Design and Method Selection:

The study employed a home-built optical trap consisting of a tunable, linearly polarized, diode-pumped, solid-state Yb3+:YAG thin-disk laser set to 1020 nm, a beam expansion region, a 100X trapping oil-immersion objective (NA = 1.25), and a modified perfusion chamber with a 300-μm spacer. Germanium nanowires were grown from colloidal bismuth nanocrystal seeds via a solution-liquid-solid process.

2：25), and a modified perfusion chamber with a 300-μm spacer. Germanium nanowires were grown from colloidal bismuth nanocrystal seeds via a solution-liquid-solid process. Sample Selection and Data Sources:

2. Sample Selection and Data Sources: The nanowires investigated had monodisperse diameters tunable from 10 to 100 nm with corresponding lengths ranging from 0.1 to 5 μm, depending on the chosen synthetic parameters.

3：1 to 5 μm, depending on the chosen synthetic parameters. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: The optical trap setup, germanium nanowires, bismuth nanocrystal seeds, and organic solvents (toluene and squalane) were used.

4：Experimental Procedures and Operational Workflow:

Nanowire dispersions were prepared in mixtures of toluene and squalane. Individual nanowires were trapped at powers ranging from 1.0 to 10 W. The assembly process involved trapping a single nanowire and moving it toward a second nanowire in Brownian motion outside the optical trap, leading to tip-to-tail nanosoldering.

5：0 to 10 W. The assembly process involved trapping a single nanowire and moving it toward a second nanowire in Brownian motion outside the optical trap, leading to tip-to-tail nanosoldering. Data Analysis Methods:

5. Data Analysis Methods: Heat transport calculations, back-focal-plane interferometry, and optical images were used to analyze the results.