Fig. 4. The balance between dissipative optical forces.
The sum of the absorption and scattering forces exerted on the r-ND under GR laser irradiation (λ1 = 532 nm) with the power Pr-ND being balanced by the scattering force exerted by the NIR (λ2 = 1064 nm) laser. For the n-ND having no absorbers, the scattering forces exerted by the GR laser with Pn-ND and the NIR laser with constant power balance each other. From these balances, the ratio of the absorption and scattering forces on the ND can be determined as (Pn-ND − Pr-ND):Pr-ND.