3D interferometric optical tweezers using a single spatial light modulator.

Hexagonal arrays of micron sized silica beads have been trapped in three-dimensions within an optical lattice formed by the interference of multiple plane-waves. The optical lattice design with sharply peaked intensity gradients produces a stronger trapping force than the traditionally sinusoidal intensity distributions of other interferometric systems. The plane waves were generated using a single, phase-only, spatial light modulator (SLM), sited near a Talbot image plane of the traps. Compared to conventional optical tweezers, where the traps are formed in the Fourier-plane of the SLM, this approach may offer an advantage in the creation of large periodic array structures. This method of pattern formation may also be applicable to trapping arrays of atoms.