Fig. 4. Stability phases for the optically bound triangular lattices.

Gray areas denote the absence of equilibrium (zero-force configuration). The green areas denote stability regions where light alone stabilizes the cluster (i.e., optical binding). Orange areas denote the region where damping is required to stabilize the cluster (opto-hydrodynamic binding). a N = 7, b N = 61, c N = 91. d Minimum damping coefficient required to stabilize the cluster versus N. A larger damping value is required at a larger N. e–f Percentages of the phase space area occupied by OB, opto-hydrodynamic binding, and no-equilibrium phase, with e representing the triangular lattice and f the square lattice. The lines linking the points are guides to the eyes only.