Construction of three-dimensional microstructure using optical beam of designed vortex-shape

Recently, the optical trapping technique has been employed to construct three-dimensional microstructures. Such three-dimensional microstructures are created from the fact that optical beams such as, a single focused Gaussian beam, multiple beams from Laguerre-Gaussian (LG) interference patterns, and Bessel beams, are able to stack microparticles on top of the other. Once these microparticles are stacked, the optical forces from the optical beam were able to hold them in place. In this paper, we demonstrate that by lowering the focused point of the LG beam below the cover slip (sample). The LG beam possesses the ability to stack multiple microparticles around its annular intensity rings and thus form a three-dimensional cubic structure. Hence we proposed a new technique of constructing microstructures, which is by creating optical fields with designed optical vortex shape. These microparticles will then be stacked according to the shape of the optical beam. This is an alternative method to obtain a desired three-dimensional crystalline structure, where shaping the optical vortices beam is used instead of using multiple beams.