Figure 3. Wavelength dependent potential well depth (open dots) the stiffness at the center of tweezers (solid dots) with different metallic nanoparticle diameters of 35 nm (◾), 45 nm (⦁), 50 nm (▴) and 55 nm (▾).

The laser fluence applied in this figure is 4 × 10⁸ W/m². The wavelength dependence of potential well’s half width for maximum (HWHM) with different particle sizes is shown as figure R3 as supplementary information.