In-Situ Characterization of Three-Dimensional Optical Matters by Light Diffraction

Jiang Lai-Dong, Dai Qiao-Feng, Feng Tian-Hua, Liu Jin, Wu Li-Jun, Lan Sheng, A. V. Gopal and V. A. Trofimov

Three-dimensional optical matters are created by combining the single beam optical trapping with the conventional Z-scan technique. Dynamic light diffraction is employed to evaluate the structure and quality of the optical matter formed at the optimum trapping power. The lattice constant of the optical matter is extracted based on the Bragg and Snell laws, showing that polystyrene spheres are nearly close-packed in the optical matter, confirmed by comparing the diffraction pattern of the optical matter with that of a colloidal photonic crystal fabricated by the self-assembled technique. The relatively broad diffraction peaks observed in the optical matter indicate that the density of disorders in it is higher than that in the photonic crystal. It is suggested that the optical matter possesses a random close-packed structure rather than a face centered cubic one.

DOI