Abstract
An apparatus of generating optical tweezers with momentum is provided for providing optical tweezers with a first momentum on a test piece. The apparatus comprises a laser source, a diffractive optical element (DOE) and a lens. The laser source is for outputting a laser beam. The DOE has a first phase-delay picture, and the laser beam forms a diffraction pattern after passing the first phase-delay picture. The lens is for receiving and focusing the diffraction pattern on the test piece to form the first optical tweezers with the first momentum. The lens has an optical axis intersecting the DOE at an optical intersection point, a geometric center of the phase-delay picture has a displacement vector relative to the optical intersection point and a direction of the first momentum is related to a direction of the displacement vector.