Apparatus and method of generating optical tweezers with momentum

A method of generating optical tweezers with momentum, applied to an apparatus of generating optical tweezers with transverse momentum for providing optical tweezers with a momentum on a test piece, the method comprising:

• (a) providing a diffractive optical element (DOE) with a phase-delay picture;
• (b) providing a laser beam passing the phase-delay picture and a lens for generating the optical tweezers on the test piece, wherein the DOE intersects an optical axis of the lens at an optical intersection point;
• and
• (c) shifting the DOE along a first direction of a surface of the DOE such that a geometric center of the phase-delay picture has a displacement vector relative to the optical intersection point and the optical tweezers has the transverse momentum;
• wherein a direction of the displacement vector is related to a direction of the momentum.

A method of generating optical tweezers with momentum, applied to an apparatus of generating optical tweezers with momentum for providing optical tweezers with a momentum on a test piece, the method comprising:

• (a) determining the momentum;
• (b) providing a diffractive optical element (DOE) with a phase-delay picture corresponding to the momentum;
• and
• (c) providing a laser beam passing the phase-delay picture and a lens for generating the optical tweezers on the test piece;
• wherein the DOE intersects an optical axis of the lens 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 displacement vector is related to a direction of the momentum.