Optical Tweezers, Optical Torque Wrench

Optical tweezers can trap microscopic particles exerting linear forces on them. Using birefringent nano-fabricated particles shaped as cylinders, optical tweezers can be expanded with torque manipulation and detection. Forces of the order of the 0.1-10 pN and torque of the order of 1-1000 pN nm can be applied and measured.