Experimental Movie 1 - Assembly of the colloidal tetramer
Our practical realization of flexible colloidal clusters is created with colloidal lock-and-key particles dispersed in a fluid medium. Below we show the steps by which a colloidal tetramer is assembled with holographic optical tweezers. The central sphere initially is trapped and moved to the center of the microscope's field of view. Additional traps are used to localize dimpled spheres, which subsequently are moved to the central sphere's surface one at a time. Each outer particle is held in place until its dimple aligns with the central sphere's surface, at which point it sticks. Once the structure is complete, the optical tweezers are turned off and the colloidal tetramer is allowed to diffuse freely in the fluid medium.